The challenge to an arbitral award for violation of legal rules is admissible when the arbitration clause expressly provides that the arbitration is to be institutional arbitration conducted according to law, with Article 829 of the Code of Civil Procedure applying in the text in force ratione temporis with respect to the date of conclusion of the contract containing the arbitration clause.
In proceedings challenging an arbitral award, the legal qualification of the substantive relationship made by the arbitral tribunal, if not contested by the appealing party and indeed relied upon as the basis for the challenge, constitutes an established premise from which to proceed in evaluating the claims brought.