The objection based on an arbitration agreement (exceptio compromissi) is of a procedural nature and raises a question of jurisdiction, which must be raised by the interested party, on pain of preclusion, in the notice of appearance filed in a timely manner (cf. Court of Cassation, No. 22748/15).
Article 50 of the Code of Civil Procedure, governing the transfer of proceedings following a declaration of lack of jurisdiction, applies also to the relationship between ordinary-court proceedings and arbitral proceedings, by virtue of the judgment of the Constitutional Court No. 223/2013, which declared unconstitutional the contrary provision contained in the original wording of Article 819-ter of the Code of Civil Procedure; consequently, upon declaring the ordinary court's lack of jurisdiction in favour of the arbitral tribunal, the parties must be granted a time limit within which to commence the arbitral proceedings.