The challenge for nullity of an arbitral award is characterised as a challenge subject to restricted grounds of review, which excludes the possibility of conducting a review on the merits against the award, with violation of rules of law pertaining to the merits of the dispute occurring when the arbitrator has committed an error of law, that is to say when the legal principle applied by the arbitrator was erroneous in relation to the established facts, upon which the court of appeal may not intervene.
The review exercisable by the court of appeal in proceedings for nullity of an arbitral award for violation of the rules of law applicable to the merits of the dispute, where violation of the regulation of equitable assessment laid down by Article 1226 of the Civil Code is alleged, is exactly the same review that belongs to the Court of Cassation when the same criticism is directed against the ruling adopted following ordinary proceedings by the appellate judge.
The concrete exercise, whether positive or negative, of the discretionary power conferred upon the judge by Article 1226 of the Civil Code to assess damages equitably is not susceptible to review by the judge hearing the challenge for nullity of the award, if the decision in this regard appears supported by reasoning free from logical defects and legal errors.