The Supreme Court of France, the Cour de cassation, rendered on 7 January 1992 its decision on multiparty arbitration: Siemens v. BKMI and Dutco . This decision has rapidly become a matter of concern among those dealing with multipartism in the field of international commercial arbitration.1 In brief, the case was as follows: three companies entered into a consortium agreement for the construction of a factory on behalf of their common employer in the Middle East. The consortium agreement contained an ICC arbitration clause expressly providing for the settlement of disputes by an arbitral tribunal composed of three arbitrators. The Dutco company as claimant filed a request for arbitration in which in reality it had one particular claim against BKMI and a second (quite dissimilar) claim against Siemens, although both claims were based on alleged breaches of the consortium agreement. The time came for the designation of the arbitrators. Whilst the claimant freely nominated its arbitrator for the approval of the ICC International Court of Arbitration, each of the defendants contended for the right to nominate an arbitrator. The ICC Court refused those contentions, considering that the defendants' disagreement over the nomination of one arbitrator in their common interest amounted to a failure to make any appointment; and the ICC Court warned the defendants of its intention to apply Article 2.4 of the ICC Rules (‘If a party fails to nominate an arbitrator, the appointment shall be made by the Court’). Eventually Siemens accepted the same arbitrator as BKMI, but it expressed its strong reservation as to the validity of the constitution of the arbitral tribunal in those circumstances. Siemens duly challenged the jurisdiction of the arbitration tribunal. The tribunal rejected the challenge by its award of 19 May 1988. Siemens then filed a recourse for annulment in the …