Dans le cadre d'un contrat de construction (« Main Contract ») conclu entre le défendeur et X, le défendeur confiait en sous-traitance au demandeur, aux termes d'un "Agreement", la fourniture, l'installation et la maintenance d'ouvrages électriques. Le demandeur prétend que le défendeur aurait abusivement retenu des sommes dues et refusé de donner mainlevée des garanties de bonne fin qui avaient été émises, en dépit de l'achèvement des travaux et bien que le défendeur ait lui-même obtenu paiement dans le cadre du contrat principal de construction. Le demandeur réclame des dommages-intérêts et la mainlevée des garanties de bonne fin. Le défendeur prétend pour sa part que la demande d'arbitrage du demandeur est irrecevable et que ses demandes sont prescrites ou frappées d'estoppel et introduit une demande reconventionnelle en dommages-intérêts. Le tribunal arbitral, dans une première sentence intérimaire, détermine le droit applicable au fond du litige, rejette le moyen de défense du défendeur relatif à l'irrecevabilité et approuve en partie/rejette en partie son argument en défense relatif à la prescription et à l'estoppel. Dans une deuxième sentence intérimaire, le tribunal arbitral rejette la demande soumise par le défendeur visant au prononcé d'ordonnances provisoires à titre conservatoire. Dans une troisième sentence intérimaire, le tribunal arbitral rejette certaines demandes du demandeur, considère que d'autres sont sans objet et accepte d'autres demandes en leur principe, reportant à plus tard la détermination du montant. La demande reconventionnelle du défendeur est considérée comme recevable, en raison de la responsabilité du demandeur, le montant des dommages-intérêts devant être fixé dans la sentence finale.

Dans la sentence finale prononcée à la majorité, le tribunal arbitral examine les diverses demandes soumises par chaque partie. Dans ce cadre, il applique le droit civil koweïtien qu'il compare aux Principes d'UNIDROIT (art. 7.1.6 (afin de déterminer si un comportement peut être considéré comme constituant une faute lourde), art. 7.4.7 (réduction des dommages-intérêts en fonction du comportement des parties), art. 7.4.3(3) (évaluation du montant du préjudice par le tribunal). Il accorde au demandeur un paiement au titre de travaux supplémentaires et une indemnité pour dommage aux ouvrages électriques. Il accorde par ailleurs au défendeur une indemnité au titre des frais généraux du siège et du site, des coûts de main d'œuvre supplémentaires et d'une certaine partie de ses frais financiers. Une compensation est opérée entre les montants adjugés à chaque partie, laissant un solde en faveur du défendeur. Les frais de l'arbitrage sont répartis entre le demandeur et le défendeur en fonction de l'admission de leurs demandes respectives (90 % supportés par le demandeur et 10 % par le défendeur).

Sur le droit applicable au fond :

'Claimant contends that the issues of the entire dispute should be governed by Kuwaiti law, either as the law explicitly chosen by the Parties (Art. 38 of the Agreement, Art. 80 of the Main Contract) or, in the alternative, as the proper law of the contract in application of all the relevant criteria of Kuwaiti and other rules of conflict of laws.

Respondent submits that the Parties made a "negative choice", i.e. each Party intended to avoid the other Party's (Kuwaiti or Italian) national law and the law of a third country was likewise excluded. Respondent explains this submission by referring mainly to Clause 38 of the Agreement where the Parties […] chose to limit the applicability of Kuwaiti law to one Party (the Claimant) and to its performance of the Agreed Works in Kuwait […] Respondent concludes from this interpretation that the Parties have chosen, as the law applicable to the merits, that part of the Kuwaiti and Italian legislation which was common to them at the time the Agreement was entered into.

The Arbitral Tribunal holds that the Parties have neither explicitly nor tacitly agreed on the substantive law.

The choice of Kuwaiti law in the Main Contract (Clause 80) between X and Respondent may not be understood to apply to the contractual relationship between the Parties as well; if the Parties had intended to refer to the applicable law clause in the Main Contract, they would have done so in the same way as they did in the first version of Clause 20 of the Agreement ("[…] in accordance with the settlement of dispute clause in the Main Contract […]").

By Clause 38 of the Agreement, Claimant (not both Parties) undertook to abide "by the regulations and customs in Kuwait" and to "follow the rules of Kuwait and Kuwaiti law" […] [The Parties] chose a wording the scope of which is obviously restricted to Claimant's and its staff's activities when performing the Agreement […] By choosing such a restricted wording in Clause 38, the Parties did obviously not deal with the much wider question as to which law shall be applicable to their Agreement in general (validity, interpretation; each Party's rights and duties; statute of limitation, etc.)

In the absence of any clear indication by the Parties as to the applicable law, the Arbitral Tribunal shall apply the law designated as the proper law by the rule of conflict which it deems appropriate (Art. 13(3) of the ICC Rules).

The Arbitral Tribunal does not deem it necessary in this case to designate a national private international law in view of the fact that all rules of conflict which may be found in legislations which have some connection with this case, indicate to Kuwaiti law as the proper law of the Agreement:

The Agreement has been signed in Kuwait. It is both Parties' understanding that the place where a contract has been concluded is an important or even the decisive criterion in their respective national (Kuwaiti and Italian) laws. It may be added that the place of arbitration is in Italy which is an additional justification to take into consideration the Italian private international law in accordance with opinions expressed formerly in the doctrine […]

The most characteristic elements of performance of the contract […] are obviously the services rendered, the work done and the goods supplied by the Kuwaiti party. The place of residence of the party which has to carry out the characteristic performance of the contract at issue is the decisive criterion in Swiss private international law, which law is connected with this Arbitration in view of the fact that the proceedings are governed, inter alia, by the Swiss Intercantonal Concordat on Arbitration […] This connection exists even if the applicability of Swiss law should be understood to be limited to procedural points only.

When looking directly to the substantive law with the closest connection, the Kuwaiti law must again be the conclusion. With the exception of the nationality and the residence of Respondent (Italy) the Agreement and its performance do not have any link whatsoever with other countries than Kuwait where the entire Agreement was discussed, concluded and performed. The price had also been agreed and paid in Kuwaiti currency.

However, in accordance with a well-established practice in international commercial arbitration, the arbitrators shall take account also of the principles generally applicable in international commerce […] This proviso is particularly justified in view of the fact that the Parties refrained from choosing explicitly Kuwaiti law as the law on the merits […]

The Arbitral Tribunal concludes that Kuwaiti law and, to the extent necessary, principles generally applicable in international commerce are applicable to the merits of the dispute.'