An arbitration clause contained in a particular contract does not extend its effects to disputes relating to another contract, even if connected with the first, pursuant to Article 808-quater of the Code of Civil Procedure, with the consequence that, in the presence of a plurality of contractual relationships between the same parties, arbitral jurisdiction remains limited solely to disputes arising from the contract in which the clause is inserted.
Pursuant to Article 819-ter, paragraph 1, of the Code of Civil Procedure, the jurisdiction of arbitrators is not excluded by the connection between the dispute referred to them and proceedings pending before the ordinary court, so that, in the presence of a plurality of claims, the existence of arbitral jurisdiction must be verified with specific regard to each of them, without the connection being able to determine the devolution of the entire dispute to the ordinary court or to the arbitrators.
An arbitration clause inserted in a public service concession contract prior to Law No. 205/2000, which refers disputes relating to fees to arbitrators, is valid where it concerns exclusively matters of subjective right relating to compensation, fees and other payments, excluded from the exclusive jurisdiction of the administrative court pursuant to Article 5, paragraph 2, of Law No. 1034/1971.
Article 209, paragraph 3, of Legislative Decree No. 50/2016, which sanctions with nullity an arbitration clause inserted without authorisation in a tender notice, does not apply to concessions entered into prior to its entry into force, being a substantive provision without retroactive effect.
A two-member arbitration clause, which refers disputes to the decision of three arbitrators, two of whom are appointed by each of the parties, may also apply in a dispute involving multiple parties when, on the basis of an ex post assessment in relation to the petitum and causa petendi, the interests at stake are grouped into only two homogeneous and opposing groups; this condition is satisfied when one of the parties formulates cross-claims, of a merely subordinate nature, against the other parties in the same group, which do not create a heterogeneity of interests in relation to the opposing party.