A challenge to an arbitral award on the ground of breach of rules of law relating to the merits of the dispute is admissible only where expressly provided for by the parties or by statute. In the context of arbitration relating to public contracts, the provision allowing the challenge of an award on the ground of breach of rules of law relating to the merits, introduced at a later date, does not extend to arbitral tribunals already constituted at the date of entry into force of the legislative amendment. In order to determine the admissibility of a challenge on the ground of breach of rules of law on the merits, the statute to which Article 829(3) of the Code of Civil Procedure refers must be identified as the statute in force at the time of the conclusion of the arbitration agreement.
Challenges to an arbitral award that amount to allegations of breach of rules of law relating to the merits of the dispute are inadmissible where such a ground of challenge is not expressly provided for, as are complaints concerning the arbitrators' assessment of fact and evidence.
A substantial disparity between the amount claimed and the amount awarded, together with the particular features of the case, justifies the order for set-off of costs made by the arbitral tribunal.