An arbitration clause providing for contractual arbitration (arbitrato irrituale) contained in a condominium by-law of a contractual nature, drawn up by the original developer and referred to in the individual deeds of purchase, has a contractual nature and affects the subjective rights of the co-owners; accordingly, its abolition or amendment by resolution of the co-owners' meeting requires the unanimous consent of all co-owners and may not be adopted by a majority pursuant to art. 1136, paragraph 2, of the Civil Code.
The referral of condominium disputes to arbitration is lawful, since art. 1137, paragraph 2, of the Civil Code, in granting each co-owner the right to challenge the resolutions of the co-owners' meeting before the courts, does not reserve absolute and exclusive jurisdiction to the ordinary court and does not preclude the arbitrability of such disputes.
In a condominium by-law, an arbitration clause and a forum-selection clause may lawfully coexist, governing proceedings with different causae petendi: the arbitration clause for disputes concerning the interpretation and performance of the by-law, and the forum-selection clause for matters that cannot be resolved by arbitration or for the enforcement of the contractual award.