Summary

EU law prohibits the conclusion by a Member State of an arbitration agreement with identical content to an invalid arbitration clause in a bilateral investment treaty between Member States.

The national court is therefore obliged to set aside an arbitral award made on the basis of such an arbitration agreement.

Reference for a preliminary ruling - Agreement between the Government of the Kingdom of Belgium and the Government of the Grand Duchy of Luxembourg, of the one part, and the Government of the People's Republic of Poland, of the other, concerning the reciprocal promotion and protection of investments, signed on 19 May 1987 - Arbitration proceedings - Dispute between an investor from one Member State and another Member State - Arbitration clause provided for in that agreement contrary to EU law - Invalidity - Ad hoc arbitration agreement between the parties to that dispute - Participation in the arbitration proceedings - Tacit expression by that other Member State of its intention to conclude that arbitration agreement - Unlawfulness.

Renvoi préjudiciel - Accord entre le Gouvernement du Royaume de Belgique et le Gouvernement du Grand-Duché de Luxembourg, d'une part, et le Gouvernement de la République populaire de Pologne, d'autre part, concernant l'encouragement et la protection réciproques des investissements signé le 19 mai 1987 - Procédure d'arbitrage - Litige entre un investisseur d'un État membre et un autre État membre - Clause d'arbitrage contraire au droit de l'Union prévue dans cet accord - Nullité - Convention d'arbitrage ad hoc entre les parties à ce litige - Participation à la procédure d'arbitrage - Manifestation tacite de la volonté de cet autre État membre de conclure cette convention d'arbitrage - Illégalité