Article 461 of the Civil Procedure Law allows a judgement to be appealed by the party that initially would not have done so, but takes advantage of the fact that the other party does so. In this case a separate appeal is filed without limits as to its scope and effects.
The reason for this possibility is a concession to the litigant who initially did not appeal, although his claims were not fully satisfied by the judgement, to rethink his initial decision not to appeal as consequence of the fact that his opponent has appealed.
This means that if the opponent had not decided to appeal, the judgement would have been final and unassailable.
Since the judgement was appealed, the Civil Procedure Law moves away from the principle of estoppel and allows the appellee to have the opportunity conferred by the opposing party's appeal to challenge, in turn, the judgement. The appeal would concern what the appellee deems unfavourable and what he would have conformed with if it had not been because the opposing party appealed.
This means that the appeal prevents the existence of formal res judicata and the appellee becomes an appellant at one and the same time and the content of his challenge is not limited by the content of the appeal filed by the other party.
The Court of Appeal shall have full powers to study and deal with the issues indicated in the writ challenging the judgement.
However, it must be borne in mind that the judgement can only be challenged when the Court serves the appeal of the opposing party.
Thus, if there is only one plaintiff and one defendant, there would be no problem of interpretation because the law provides for the notification of the appeal in writing to the other party. Consequently, at the time of opposition to it, the judgement may be challenged and the appeal be subsequently served to the main appellant.
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