Claimant's search for the capital required to finance an aeronautical manufacturing and marketing project led it to take up relations with a company of which Respondent is the successor. The two parties formalized their partnership through various agreements, including a Shareholders Agreement. The dispute concerns the latter. Claimant requests the Arbitral Tribunal to pronounce the termination of the Agreement owing to breach by Respondent and to award it damages for the harm suffered. In turn, Respondent claims the Agreement was invalid or inapplicable, that it was justified in withdrawing, and that the Agreement was characterized by hardship, entitling it to damages. It bases its claims on the <b>Unidroit Principles</b>, notably Articles 6.2 (hardship), 3.10 (gross disparity) and 1.7 and 2.15/2 (lack of good faith), as a reflection of international trade usages. The Arbitral Tribunal rejects both the claims and the grounds upon which they are based. It decides that there is no justification for the alleged hardship and that the Agreement and the arbitration clause it contains are valid and applicable. It then considers the question of lack of good faith, raised by Claimant, and that of failure to comply with the undertaking not to compete, raised by Respondent. The Arbitral Tribunal dismisses the former and, whilst recognizing the validity of the undertaking not to compete, declares that it lacks jurisdiction to decide this request, which is not included in the Terms of Reference. It comes to the conclusion that the Agreement should not be terminated on the ground of Respondent's default and that it was unjustified for the latter to withdraw. Its finding is that the Agreement came to an end rather through mutual misunderstanding, with no retrospective effects. The parties are ordered to bear arbitration costs in equal proportions.

With respect to the applicable law:

'Respondent has claimed that these proceedings are an arbitration that is international and subject to statutory rules and to institutional procedures; that the arbitration's international character is determined by the fact that both Respondent's head office and the locus destinatae solutionis of a considerable part of the services that are the subject of the disputed business relationship are situated abroad (Article 832 of the Code of Civil Procedure), as well as by the fact that this is an institutional arbitration governed by the Rules of Arbitration of the International Chamber of Commerce; and that the statutory nature of the arbitration is inherent in the fact that this is a legal arbitration, with application "for every purpose" of Italian law . . .

This constitutes the premise on the basis of which Respondent pleads to "recall that in accordance with Article 834 of the Code of Civil Procedure international arbitration should in all cases also take into account, as regards the relevant legal rules applicable, commercial usages"; to claim that lex mercatoria "is thus necessarily an integral part, even where binding rules of procedural practice apply, of substantive Italian law, under which, as indicated in the contract, the present case must be appraised and the dispute decided by the Arbitrators"; to engage the "Principles of International Commercial Contracts" drawn up by Unidroit, as an authoritative source of knowledge of international trade usages.

In its written response . . . Claimant considered inappropriate Respondent's appeal to Unidroit Principles, inasmuch as these apply only when the parties have agreed that the contract be subject to them; inasmuch as the Unidroit Principles "shall be applied when the parties have agreed that their contract be governed by them" and "they may be applied when the parties have agreed that the contract be governed by them"; inasmuch as the doctrine expounded by the author of the commentary on the preamble and the first, second and fourth chapters of the Unidroit Principles, has made it clear that the Unidroit Principles are not the subject of an international agreement and do not have binding force in themselves, but can acquire validity only by the will of the parties; that one of the fundamental principles of the Unidroit Principles is that of freedom of contract; and inasmuch as Article 11 (Freedom of Contract) stipulates that: "The parties are free to enter into a contract and to determine its content". Claimant observes that it is precisely in their exercising of contractual autonomy, a cardinal principle endorsed by Article 1322 of the Civil Code and by Article 41 of the Constitution, that the parties agreed Clause 17 of the Shareholders Agreement, the applicability of Italian law, and did not make any reference to the Unidroit Principles.'

On the question of whether or not the Shareholders Agreement is characterized by hardship:

'Respondent concluded by asking the Arbitral Tribunal to declare that the Shareholders Agreement entered into by the parties . . . causes grave hardship to the detriment of Respondent. . . . Respondent has attempted to identify the hardship in the unzumutbare Härte of German experience, i.e. in the excessive disparity in the contract or in some of its clauses, with excessive advantage to one of the parties, to which the Unidroit Principles also refer . . . [and to show] that the disparity between the services rendered by the two parties is vast. . . . Respondent therefore maintains that the services rendered by Claimant were no more than abstract "Supports", in part not corresponding to the truth and in part, on the contrary, laying burdens . . . exclusively on Respondent. . . . Respondent insists that the gross disparity between the obligatory services rendered by the parties . . . has repercussions for the validity and efficacity of the partnership agreement . . .

Furthermore, Claimant, having considered inappropriate Respondent's appeal to the Unidroit Principles on the basis of the general considerations described above, has also pointed out that, in any case, Articles 3.10 and 6.2.2 of the Unidroit Principles referred to in Respondent's concluding plea do not permit a finding of the existence of the alleged grave hardship complained of, i.e. the disparity between the services in the contract, to the detriment of Respondent; that Article 3.10 of the Unidroit Principles, in particular, stipulates that there must exist two presuppositions in order for the grave hardship principle to be applicable, viz. that "there must be a serious disparity between the parties' reciprocal rights and obligations which gives an excessive advantage to one party" and that "the excessive advantage must be unjust, that is to say that one party must have taken excessive advantage of a dependency, a state of economic necessity, urgent needs or lack of foresight, ignorance, inexperience, or the other party's disablement in conducting the negotiations"; that these presuppositions are not present in this case.

The Arbitral Tribunal considers that the abnormal hardship complained of by Respondent does not exist, and that it cannot therefore accept the connected claim aimed at obtaining from the Arbitral Tribunal the finding that the Shareholders Agreement is invalid or void. And this for many concurrent reasons.

Firstly, it notes that Respondent's claim aimed at obtaining from the Arbitral Tribunal the finding that the Shareholders Agreement is invalid or void is based sometimes on the lex mercatoria and sometimes on the Unidroit Principles; it also notes that, notwithstanding the textual references to "hardship", in basing its defence claim on the Unidroit Principles Respondent does not limit itself to pleading Article 6.2.2 of the Unidroit Principles, but also invokes Article 3.10, which deals not with "hardship" but with "gross disparity".

In the first place, the Arbitral Tribunal considers that the reference to lex mercatoria and the specific appeals to the Unidroit Principles do not constitute sufficient justification for sustaining Respondent's claim that the Shareholders Agreement should be declared invalid or void, for various reasons.

The first reason appertains to the fundamental judicial rule that the onus is on the party that has invoked the application of the lex mercatoria and of the Unidroit Principles to prove that the rules invoked are part of lex mercatoria so far as concerns assumptions that may be of legal relevance and so far as concerns the consequences of disparity between the parties to the agreement, proving the existence of interpretative and applicative trends in international commercial circles supporting the interpretation that is put forward. This Respondent has failed to do, and therefore the appeal to the Unidroit Principles as regards gross disparity and hardship is not valid: it having been made clear that the Unidroit Principles are not part of normative sources of production, and that they are designed to constitute a uniform model for regulating the negotiation of contractual relations, it is also clear that, as regards their relationship with lex mercatoria and international trade usages, the Unidroit Principles are only partly declaratory, being innovatory in many respects. In other words, although the Unidroit Principles constitute a set of rules theoretically appropriate to prefigure the future lex mercatoria should international commercial practice adapt to the Principles, at present there is no necessary connection between the individual Principles and the rules of the lex mercatoria, so that recourse to the Principles is not purely and simply the same as recourse to an actually existing international commercial usage.

The second reason, which comes into play even if one assumes that the rules on gross disparity and on hardship invoked by Respondent actually come under lex mercatoria and the practices of international trade in particular, consists in a widespread interpretative trend, which the Arbitral Tribunal agrees with, whereby, where the parties have expressly and precisely identified the law applicable to the relationship established between themselves and, in particular, have, as in the present case, identified it as a national law, the possibility of shaping the procedure in accordance with rules that do not belong to the national system of rules to which the contracting parties have referred is precluded. In the light of the above-mentioned trend, it is not sufficient, in order to make applicable lex mercatoria, for provisions that may exist in the national legal system to which the contracting parties have referred to contain references to lex mercatoria: that is to say, where the parties have availed themselves of the possibility of choosing the legal system applicable to their relationship, no-one can substitute himself for these parties in the choice of applicable laws, adapting the system at his discretion. All of the above, which applies even in respect of the widespread referrals to lex mercatoria that can be found in French and Swiss legislative practice, has even more validity with regard to Article 834 of the Code of Civil Procedure, where the reference proves to be more tenuous. On the one hand, it should be borne in mind that Article 834 of the Code of Civil Procedure refers to "international commercial usages", while lex mercatoria is an expression of notoriously very wide scope and interpretation, and could even be termed imprecise and debatable; in this light, there is no merit in appealing to Article 834 of the Code of Civil Procedure as a provision legitimising the application of lex mercatoria as the basis for making the Shareholders Agreement void and invalid. On the other hand, it should be borne in mind that the appeal to international commercial usages contained in Article 834 of the Code of Civil Procedure must be linked with the national legal regulations to which the provision appealing to international commercial usages belongs. If one refers to institutions that are specifically regulated by Italian law or, in any case, that produce rules that are incompatible with the regulations of Italian law, international commercial usages cannot take precedence over national law; thus Article 834 of the Code of Civil Procedure, which does not allocate any precedence to the various sources, does not grant to any international commercial usages that can be taken into account, in the interpretation of a contract, supremacy over the provisions of Italian law. Thus, international commercial usages are of strictly interpretative and integrative value, to the extent that there are gaps in national regulations that could usefully be filled by the aforesaid usages; this means that Article 834 of the Code of Civil Procedure refers to international commercial usages as a source of law, but that those practices have their place and are treated in a similar way to custom; all the more so when the parties have chosen national law as the law applicable to their relationship, it being certainly not possible, in such a case, to substitute international commercial usages for the national law chosen by the parties with regard to institutions, actions, and effects, for which the latter makes special provision. Since the presuppositions for juridical relevance and the consequences of the contractual disparity, whether at the start or that occurred after the conclusion of the contract, are specifically regulated by Italian legislation, which recognizes the remedies of rescission and cancellation of the contract because the contract has become excessively onerous, the appeal to lex mercatoria or to the Unidroit Principles does not permit application of the doctrine of gross disparity and of hardship in order to bring into greater focus the contractual disparity - whether original or occurring later -beyond the limits of or with effects different from the presuppositions that are relevant in law and from the actual consequences of rescission and of cancellation of the contract because it has become excessively onerous.

The third reason is found in the nature of the provisions of Italian law concerning the invalidity and nullity of contracts that are considered to come under the rules of public policy. The binding nature of these provisions, which flows directly from the obligation emphasized above, precludes the possibility that the provisions of Italian law concerning hypotheses and presuppositions of invalidity or nullity of contracts be set aside by reference to lex mercatoria. In a more specific sense, this constitutes a further proof of the above argumentation in that, given that the parties opted for Italian law as the law governing their contractual relationship, the rules on gross disparity and on hardship invoked by Respondent are rendered inapplicable in the present case, even if one assumed that they are part of lex mercatoria and, in particular, international commercial usages.

In any case, even if lex mercatoria and the Unidroit Principles were applicable in this case, Respondent's claim aimed at obtaining from the Arbitral Tribunal the finding that the Shareholders Agreement is invalid or void, could not, in the Arbitral Tribunal's opinion, be sustained, either with regard to the supposed gross disparity, or with regard to the supposed hardship.

As for the possibility of accepting the aforesaid claim under the heading of gross disparity, the Arbitral Tribunal considers that there are impediments even on the formal level. In the first place, the Terms of Reference refer only to hardship, and lack any reference to gross disparity, which Respondent has not, in this forum, invoked, not even requesting, still less obtaining, its inclusion as part of the Terms of Reference. On the other hand, and in the second place, while Respondent has detailed its own submissions it has again failed to refer to gross disparity.

And, even if one wished to ascribe the notion of gross disparity to the disputed issues that are the subject of this arbitration according to the principle of jura novit curia, supposing a mere error on the part of Respondent and bearing in mind that Respondent's claim is aimed at asserting the original disparity in order to make the Shareholders Agreement invalid or void, the said claim could still not be sustained, given the absence of the presuppositions.

In this regard, the Unidroit Principles specify that the consequences of the gross disparity consist in amending the contract at the demand of one party or, alternatively, in annulling the contract. In this case, there being nothing in the documents to show there was a request to amend the contract based on the original contractual disparity, which Respondent refers to for the first time at the start of the arbitration, the only consequence can be the annulment of the Shareholders Agreement, for which, however, the presuppositions to such an end required by the Unidroit Principles invoked by Respondent are lacking.

And, in fact, Article 3.10 of the Unidroit Principles asks that the following factors be taken into account when determining the "injustice" of the disparity: the fact that the advantaged party (in this case Claimant) had taken advantage of the dependent state, economic difficulties or immediate needs of the disadvantaged party (in this case Respondent), or of the ignorance, inexperience or lack of negotiating skills of the disadvantaged party (in this case Respondent). Not only has Respondent failed to prove the presuppositions alluded to, but also circumstances have emerged such as to exclude them totally: not only has Respondent failed to prove that, at the time the contract was concluded, it was in a state of dependence, economic difficulty or immediate need, but it has also emerged that it was Claimant who was in economic difficulties; not only has Respondent failed to prove that, at the time the contract was concluded, it was incompetent, ignorant, inexperienced, or lacked negotiating skills, but also these conditions are excluded by Respondent's status.

It seems rather unlikely that Respondent was languishing in a state of ignorance, bearing in mind the lengthiness of the negotiations prior to the conclusion of the Shareholders Agreement . . .

On the other hand, whatever state it was in, ignorance would not be relevant to the notion of gross disparity, inasmuch as Article 3.10 of the Unidroit Principles gives relevance to the disadvantaged party's being in ignorance only if this ignorance was of circumstances that came about later or, if prior to the conclusion of the contract, of circumstances that were not known and could not have been known at that time. In the present case, because of the considerations just described, the Arbitral Tribunal holds that the extent of the contributions requested could reasonably have been foreseen by a professional operator in the aeronautical sector, by exercising the due diligence expected from a professional from the sector to which Respondent belonged. All the more so since the facts brought forward by Respondent in its own defence, following investigations carried out in the course of the arbitration, demonstrate not only and not so much that many of the facts learnt by Respondent ex post were objectively knowable beforehand, but above all that Respondent was negligent in its preliminary investigations at the stage of the pre-contractual negotiations, which constitutes confirmation of an attitude that cannot but assume importance as regards the application of the invoked Article 3.10 and, particularly, as regards the presupposition of the "unknowability" of such facts by a diligent professional.

. . . considering that the cited Article 3.10 attaches importance not to what was purely subjectively believed to be the case by the disadvantaged party, but rather to what was objectively knowable, the remedy of annulling the agreement due to gross disparity purely because of the disadvantaged party's misplaced trust, both in general and in the present case, remains precluded.

Just as there are no presuppositions on which one could base annulment of the Shareholders Agreement due to gross disparity, it must also be pointed out that, under the invoked Article 3.10, an assessment aimed at verifying the presupposition of the original disparity must take into account the nature and purpose of the contract whose annulment is sought.

As regards the purpose of the Shareholders Agreement, of prime importance is the fact that the contract was aimed, on the one hand, at regulating the contributions from each of the parties, in the common knowledge of the economic difficulties in which Claimant found itself, which is therefore connected to the common knowledge that it was on Respondent that the economic burden would fall most heavily; and at the same time that the parties' contractual positions would be brought back into balance . . . This does not permit the hypothesis of an alleged original disparity, not only given the objective content of the economic and legal transaction taken in its entirety, but also bearing in mind that the assessment carried out a posteriori in the interpretation of the contract cannot replace the free demonstration of the parties' individual autonomy, the person interpreting the meaning of the contract therefore being in no position to substitute himself for the parties in the free determination of the negotiating balance, nor to invoke the aforesaid assessment to allow escape from an obligation freely assumed purely because it had become disagreeable.

As regards the nature of the Shareholders Agreement, of prime importance is the fact that the two connected contracts of which the united economic and legal joint-venture operation agreed between the parties consists are partnership contracts. This means that the services that the parties undertook to provide had the nature of contributions to a common enterprise . . .: thus there is no relationship of equivalence between the services that Respondent and Claimant undertook to provide under the Shareholders Agreement and, consequently, it is by no means certain, with regard to the relationship between the above-mentioned services, that the alleged original contractual disparity should even be evaluated.

As regards the possibility of accepting, under the heading of the alleged hardship, Respondent's claim aimed at obtaining a finding from the Arbitral Tribunal that the Shareholders Agreement is void or invalid, even if the Unidroit Principles invoked in this regard by Respondent came under lex mercatoria, and it were to be held that the latter is applicable to the present case, the Arbitral Tribunal considers that in the present case there would be no presuppositions of hardship and, therefore, no grounds for a finding of invalidity or nullity.

As regards the absence of presuppositions of hardship, it is enough here to point out that these are listed under Sections A to D of Article 6.2.2 of the Unidroit Principles, which stipulate the only concurrent and supplemental conditions that may be cited when pleading hardship; that, in particular, hardship postulates an event that took place that was the cause of the contractual disparity; that in the present case Respondent has not alleged that such an event occurred, and that this event cannot be the alleged cognizance that third parties owned the rights to make use of the project, since we are dealing here with an original fact that may be cited solely in relation to gross disparity, although even then, as we have written, it could not assume any importance in this respect; that the notion of hardship also postulates that the disadvantaged party was not contractually bound in respect of the event that occurred that was the source of the contractual disparity; that in the present case Respondent was aware - or, at any rate could have been aware, for the reasons already described - that this was an old project, and that responsibility for the technical aspects, the certification, the marketing, and any finance necessary for the joint venture would fall upon it, and that it would assume the related risk; that no unforeseen circumstances had even emerged while the contract was being concluded such as to aggravate that risk, taking into account, after all, that Respondent declared its intention of extricating itself from its obligation only two months after the Shareholders Agreement had been finalized.

As regards the absence of presuppositions for a finding of invalidity and nullity, it is worth noting that Article 6.2.3 of the Unidroit Principles specifies that the consequences of hardship are that the contract be either amended or terminated. Given that neither party has requested that the contract be amended, Respondent's application to have the Shareholders Agreement declared invalid or void ab origine cannot be accepted, on the basis of the same rules invoked by Respondent, which would in any case only have allowed the possibility that the contract might have been terminated because of the hardship.'

On the question of good faith:

'. . . Respondent concluded by asking the Arbitral Tribunal to declare that Claimant had violated Article 1337 of the Civil Code and of the corresponding rules of the lex mercatoria, at least in the objective meaning of the criterion for good faith.

. . . In its concluding pleading, Respondent particularly emphasised in jure that according to commercial usages, which, in Respondent's opinion, and also according to Article 834 of the Code of Civil Procedure, the arbitrators should take into account, good faith should be evaluated not in a subjective sense, according to the equation "lack of good faith = fraud", but in an objective sense; that in the Unidroit Principles, in which good faith is mentioned repeatedly, it is always evaluated by reference not to the internal standards of various national legal systems, but to the standards of international business practice, according to which the obligation to observe it is violated not only in the case of fraud, but also in that of simple negligence, thoughtlessness, and rashness; that in contract law acting in good faith refers to a purely objective test: if a party acts in an unreasonable and inequitable way, it will not be a defence to say that he honestly believed his conduct to be reasonable and equitable; that this is the correct approach to the concept of good faith in the present judgement, too, in which the way in which Claimant conducted the pre-contractual negotiations was perhaps, but not necessarily, motivated by bad faith in the sense of conscious deceit, but could also have been caused simply by negligence, thoughtlessness, or inexperience, but that, if this were the case, there would be no grounds for not deeming it to have been objectively bad-faith behaviour, in a business relationship such as the present, which is subject to Italian law, whose legal system also includes the lex mercatoria.

. . . Claimant has contested the validity of Respondent's thesis, according to which Claimant had acted in bad faith in relation to Respondent, involving Respondent . . . in a project that could objectively lead to bankruptcy.

. . . Claimant maintains that the general clause on good faith, as a criterion for interpreting contracts inter partes and as a code of behaviour in their performance, far from being violated by Claimant, has been violated by Respondent. In Claimant's view, not only was it solely Respondent which had failed to discharge its specific obligations under the Shareholders Agreement, but it had also not performed the contract in good faith.

According to Claimant, Respondent violated the general clause of good faith, above all in the pre-contractual negotiations: this on the presupposition that good faith binds the parties to joint contractual responsibility; negatively speaking, good faith carries the obligation of not intentionally encouraging misplaced trust, not speculating on the basis of misplaced trust, and not contesting reasonable trust, however engendered in the other party . . .

According to Claimant, Respondent also violated the general clause on good faith in the performance of the contract: this on the presupposition that good faith carries an obligation of safeguard, which requires each of the parties to act in such a way as to protect the other's interests and, therefore, to safeguard the economic value of the contract . . .

. . . Respondent has confirmed that for Respondent the case centres principally on Claimant's violation of the duty to behave in good faith when conducting the negotiations and drawing up the contract; has contested Claimant's thesis that Respondent had violated the general clause on good faith "following the 'misplaced' trust that Claimant, 'who claimed . . . to have thus overcome some of the problems connected to the development, production and sale of the . . .', had 'intentionally engendered'"; has confirmed that it is referring, when maintaining that Claimant "had violated the canons of good faith . . . to the use of that term in the sense that it had objectively violated them, as also and in particular understood by the rules of the lex mercatoria (and by the Unidroit Principles, especially Articles 1.7 and 2.15/2). We do not therefore wish to accuse the other party of having acted fraudulently. Fraud there may have been, perhaps; we are not asserting that there was, in the sense of defective consent within the meaning of Article 1439 of the Civil Code, but it is from the violation of Article 1337 of the Civil Code that we derive Respondent's right to receive compensation for the damages derived therefrom". . . .

The Arbitral Tribunal holds that, with regard to Respondent's appeal to lex mercatoria in support of Claimant's alleged violation of Article 1337 of the Civil Code, the reasons already given above also apply here, and the Tribunal therefore holds that the claim is devoid of merit.

As regards Respondent's claim that Claimant has violated Article 1337 of the Italian Civil Code, that is to say, as regards the claim that Claimant violated its obligation to act in good faith under Article 1337 of the Civil Code, the Arbitral Tribunal holds that the question does not fall within its competence, bearing in mind the arbitration clause. This is on the grounds that Article 1337 of the Civil Code pertains to the course of the negotiations and to the drawing-up of the contract, and thus to facts and behaviour preceding the conclusion of the contract that are the subject of disputes not amongst those covered by the arbitration clause providing for those disputes to be referred to arbitrators. Furthermore, and in the same sense, the Arbitral Tribunal agrees with the school of thought in interpretation which, although it recognizes the far-reaching nature of pre-contractual responsibilities sanctioned by Article 1337 of the Civil Code, nevertheless leaves outside the contractual realm - and, in particular, outside the realm of disputes concerning the contract that are the subject of the arbitration clause - the facts of a claimed violation of the obligation to act in good faith at the stage of the pre-contractual negotiations, which is the complaint of Respondent.

In this regard, it should also be noted that Respondent has not asked the Arbitral Tribunal to pronounce on whether the Shareholders Agreement can be annulled on account of error or fraud on the part of Claimant connected to the latter's complained-of violation of the obligation to act in good faith during the pre-contractual negotiations. It remains the case, nevertheless, that Respondent is entitled to take the matter before the courts in order to have assessed Claimant's complained-of pre-contractual responsibility, and that the latter may consequently be ordered to pay compensation for damages should the presuppositions be accepted by that court.'

With respect to the assessment of damages:

'The President of the Arbitral Tribunal, while conscious of the difficulties involved in resolving the final issues put forward by his co-Arbitrators who, on the point of the an debeatur, agree on the solution adopted, but do not agree on the effects and on the amount of the costs to be divided between the parties, considers that recourse must be made to formal criteria for the solution, aided - where necessary - by recourse to "equity", which is permitted by Italian law for the assessment of damages, under Article 1226 of the Civil Code.

As for the effects of the dissolution of the agreement by mutual dissent, while having a high regard for the doctrinal thesis set out by the arbitrator nominated by Respondent, the President of the Arbitral Tribunal considers it preferable to adhere to another thesis, one also subscribed to in case law, according to which the cancellation of a contract by mutual dissent, in contrast to cancellation due to breach of contract, does not, in the absence of a specific negotiated agreement, have the retroactive effect that for the latter is provided for by Article 1458, paragraph 1, of the Civil Code; thus, when a contract is terminated by mutual dissent, it does not lead to the restoration of the status quo ante, which must, in fact, be deemed to be implicitly excluded by the effect of the comprehensive assessment given by the parties by the act of terminating the contract. It follows that, should a contract be dissolved by mutual dissent, the parties' only obligation is to effect the usual restitutions deriving from the contract's dissolution, whilst any other residual effects (compensation for damages or reimbursement of expenses), which are the specific consequences of facts constituting breach of contract, should take place following an appropriate agreement between the contracting parties; and this in the sense that, if the parties have made no provision for apportioning the losses following the dissolution, one must have regard solely to the restitutive effects, which are not retroactive. This means that each of the parties must return to the other the amount it had contributed at the beginning of the operation.'