In matters of arbitration, pursuant to Article 819, paragraph 1, of the Code of Civil Procedure, arbitrators may resolve, without the authority of res judicata, all questions relevant to the decision of the dispute, including the preliminary question of nullity of an administrative act underlying the contract that is the subject of the arbitration proceedings. This constitutes an incidental determination that the civil court – and, consequently, arbitrators – may make for the purposes of potential disapplication of the measure, without requiring prior annulment by the administrative court.
The challenge to an arbitral award for breach of the limits of the arbitration agreement, pursuant to Article 829, paragraph 1, number 4, of the Code of Civil Procedure, cannot be based on the circumstance that the arbitrators have dealt incidentally with the validity of the administrative resolution and the contract arising therefrom, given that such consideration falls within the powers of arbitrators as a preliminary question of merit necessary for the decision of the dispute submitted to their jurisdiction.