In proceedings opposing a payment order, the objection that the ordinary court lacks jurisdiction by reason of an arbitration agreement must be raised, on pain of forfeiture under art. 819-ter, co. 1, cod. proc. civ., in the writ of opposition, as the opponent’s first defensive pleading.
In the absence of specific supranational rules, an objection that the dispute is referred to arbitration is to be examined under Italian procedural law, in application of the lex fori principle.