In proceedings for the challenge of an arbitral award on grounds of nullity, the principle of the internal expansive effect of reversal applies, pursuant to Article 336, paragraph 1, of the Code of Civil Procedure, whereby the reversal, even if partial, of the decision results in the invalidation of the part relating to costs, with the consequent power and duty of the appellate court to comprehensively reassess, even of its own motion, the allocation of procedural costs, including those of the arbitration proceedings, in light of the overall final outcome of the dispute.
In proceedings following remittal after cassation of the judgment rendered in the challenge to the arbitral award, all issues upon which the court hearing the challenge has expressly ruled and which were not raised in the appeal to the Court of Cassation constitute res judicata, with the consequence that such issues may not be raised again in the proceedings on remittal, and only those issues declared to have been rendered moot in the quashed judgment may be re-examined.