The Validity of Res Judicata and Its Evolution in the Rules of Consolidation of the Claims and Grounds in the French Legal System

Among the rules of civil procedure law, there is the validity of res judicata which it has been a basic rule of law from a long time ago and citing this rule as a procedural objection during the claim causes a permanent barrier to the proceedings. In general, the implementation of this rule requires the existence of the triple conditions including the unity of the subject, the litigants and the cause of action.
Recently, the judicial precedent of France, the country of origin of the rule, has given the two other rules in order to eliminates the inefficiencies and to correct implementation of the validity of res judicata; The rule of consolidation of the grounds which means that the plaintiff of the initial claim is required to present all the causes and directions on which the claim can be based, otherwise, the claim is subject to the validity of res judicata. This rule has been noticed in a known French judicial case named "CESAREO".
The second rule, which concerns the consolidation of claims, stipulates that the plaintiff of the initial claim is obliged to utilize all available defenses and, if necessary, raise a counterclaim. Otherwise, following the introduction of a separate claim against the plaintiff, the issue will be deemed resolved. This rule was established by the commercial branch of the Supreme Court of France in a judgment concerning an arbitration case. Notwithstanding the existence of opposing views on these two rules, the legal system of France, in its traditional implementation of the rule of res judicata, is founded upon the purpose of establishing this rule. This includes the one-time judicial proceeding of the judicial matter, which requires the existence of the three conditions. Consequently, a decision must be made about it forever. In order to achieve this objective, the authors have selected and analyzed a judgement pertaining to a trademark dispute, which was issued by a French appellate court and subsequently confirmed by the Supreme Court of France. In accordance with the aforementioned rule, the French court resolved to consolidate the subject, litigants, and cause of the claim, despite the discrepancy in the subject matter of the initial and subsequent litigation, the dissimilarity in the litigants involved in the two claims, and the fact that the referenced legal articles are not identical. Ultimately, the court ruled that this rule encompasses the second claim as well. Consequently, all orders issued by the courts are subject to this rule, including judgments.
This article seeks to examine the question of how the aforementioned rule could be implemented in the French legal system, and to what extent it could be applied in the context of the Iranian legal system. A review of this case demonstrates that the application of the aforementioned rules is equitable and just. However, the formal unification of the three conditions does not align with the principle of the rule of res judicata, as evidenced by the judgment in the Bordeaux case. Similarly, the aforementioned judicial orders are subsumed within the aforementioned rule, akin to judgments. This is in accordance with the decisions of the French courts, which are at odds with certain tenets of Iranian doctrine. Moreover, the implementation of this rule is permitted in the appellate court, provided that the counterclaim is raised in accordance with French judicial precedent, which differs from the Iranian approach. This article provides an overview of the aforementioned rules and examines how French judges interpret the triple conditions and their implementation, with reference to French judicial precedent and a case from among the issued court verdicts. A comparison of the Iranian and French judicial precedents is a valuable exercise, as it reveals the shortcomings of the Iranian legal system. The implementation of this rule is rigid and inflexible, leading to numerous proceedings on the same matter. While some judges attempt to address this issue through their individual ingenuity, a more comprehensive solution is necessary to align the Iranian legal system with the French judicial precedent outlined in this article.