An arbitration clause devolving to arbitrators the resolution of disputes relating to the performance of a lease contract does not operate in the summary phase of proceedings for validation of eviction, given the mandatory functional jurisdiction of the ordinary judicial authority in such special phase. The effectiveness of the arbitration clause is manifested only upon transition to the full cognition phase, in which the judge must divest himself of the dispute and refer it by judgment to the decision of the arbitrator.
An arbitration clause contained in a lease contract, providing for the devolution of disputes to a sole arbitrator with application of contractual arbitration (arbitrato irrituale), where validly agreed and effective, entails the lack of jurisdiction of the ordinary judge to adjudicate on the merits of the case, with consequent obligation to refer the dispute to the decision of the arbitrator designated according to the contractually established procedures.