The objection of arbitration constitutes a question of lack of jurisdiction of the state court which must be examined as a matter of law pursuant to Article 819 ter of the Code of Civil Procedure.
In case of doubt, the arbitration agreement is to be interpreted in the sense that arbitral jurisdiction extends to all disputes arising from the contract or from the relationship to which the agreement refers, in application of the principle of favor arbitrati set out in Article 808 quater of the Code of Civil Procedure.
Where in the arbitration clause the parties identify the disputes to be referred to arbitrators by reference to specified abstract categories, in the absence of an express contrary intention, the clause must be interpreted broadly, with reference to all disputes relating to claims having their cause of action in the contract, in order to avoid the fragmentation of litigation between the state court and the arbitrators.
Where the number of arbitrators is not specified and the parties do not agree thereon, the default provisions of Article 809(3) of the Code of Civil Procedure apply, without such lacuna affecting the validity of the arbitration clause.