An arbitration clause providing for informal arbitration does not require specific written approval pursuant to Articles 1341 and 1342 of the Civil Code, unlike a clause establishing formal arbitration.
The requirement of written form ad substantiam required for the validity of an arbitration clause does not presuppose that the contractual intention be expressed in a single document bearing the simultaneous signature of both parties, but may also be satisfied through an exchange of correspondence containing respectively the proposal and acceptance of the submission of the dispute to arbitrators.
An arbitration clause relating to disputes concerning the interpretation, conclusion and termination of a contract encompasses within its scope of application claims for damages for breach of contract, which pertain to the performance phase of the contract.
Non-compliance with the principle of adversarial proceedings occurring during informal arbitration is relevant exclusively for the purposes of challenging the award under Article 1429 of the Civil Code, as an error which, arising from violation of the limits of the mandate conferred upon the arbitrators, has vitiated the contractual intention expressed by the latter.
Objections relating to the quantification of contractual penalties do not fall within the typical normative cases provided by Article 808-ter of the Code of Civil Procedure for challenging an informal arbitral award, as they concern the application of rules of contractual interpretation or errors of judgment that cannot be censured through challenge of the award.
Regarding contracts for which the law requires written form ad substantiam, the production in proceedings of the contract on the initiative of the contracting party who has not signed it is equivalent to signature.