Res judicata (autorité de la chose jugée)

Res judicata is the authority attached to a judicial decision that prevents a dispute already decided from being brought before the court again. Article 1355 of the French Civil Code makes it subject to a threefold identity of subject matter, cause of action and parties acting in the same capacity. Article 480 of the French Code of Civil Procedure attaches it, from the moment it is delivered, to a judgment that decides all or part of the main issue in its operative part.

Conditions and scope

Res judicata attaches only to the operative part of the decision, not to its reasoning, according to settled case law of the Court of Cassation. The Court further holds that the claimant must put forward, in the proceedings on the first claim, all the grounds it considers capable of supporting it, so that a new claim with the same subject matter, based on a different legal ground, is barred by res judicata. Res judicata is raised by way of a plea of inadmissibility, which may be put forward at any stage of the proceedings.

Provisional decisions

Orders made in summary proceedings do not have res judicata effect as to the main issue, and they may be varied or set aside in the event of new circumstances. The same applies to ex parte orders, which remain provisional. The court hearing the merits is therefore not bound by the assessment made in summary proceedings of the likelihood of infringement or of the seriousness of a validity challenge. A decision given under the expedited procedure on the merits, by contrast, rules on the merits and carries res judicata effect.

Specific features in intellectual property

A decision ordering the invalidation of the patent has absolute effect, subject to third-party opposition (tierce opposition), and a decision declaring the invalidity of a trade mark has the same effect. A decision dismissing an invalidity claim, by contrast, binds only the parties, and a third party remains free to challenge the right. In infringement matters, the cause of action is assessed by reference to the facts submitted to the court, so that later acts or different products may found a new action.

Key points

Res judicata is decided from the first instance onwards, through the principle that all grounds must be raised at once. All available legal bases should be invoked from the outset, as a second action based on an omitted ground would be inadmissible. The claims intended for the operative part must also be drafted with precision, since only the operative part acquires res judicata effect. A favourable summary order never removes the need for a decision on the merits.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. Where the question arises in a real case, the useful moment is almost always before proceedings are issued.

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