Journal of Historical Research, Law and Policy 3115-7505 In Press 2027 07 01 Analysis of the Principles and Formalities Governing Civil Procedure in French Law with Emphasis on the Rules of Formal and Substantive Nullity in the Code of Civil Procedure Analysis of the Principles and Formalities Governing Civil Procedure in French Law with Emphasis on the Rules of Formal and Substantive Nullity in the Code of Civil Procedure 1 16 EN Journal Article 2026 04 08 <p>This study examines the principles and formalities governing civil procedure in French law and, through explicating the fundamental dichotomy between “formal defects” and “substantive defects” in procedural acts and measures, analyzes the criteria of nullity and the mechanisms for remedying such defects. In the first section, formal nullity and its scope are analyzed on the basis of rules such as the necessity of explicit statutory provision for nullity, the requirement to prove prejudice, the timing for raising procedural objections, and the possibility of curing defects through subsequent procedural actions. This section demonstrates that French law, through a functionalist approach, recognizes formal nullity only where essential procedural formalities have been violated or substantial prejudice has occurred. In contrast, substantive nullity, which pertains to legal capacity, standing, or representation, may be invoked without the need for an explicit statutory provision or proof of prejudice and is subject to more severe sanctions because it concerns the fundamental validity of judicial proceedings. The study further addresses issues such as the nonappearance of litigants, the legal consequences of absence, and the role of these matters in the validity of judicial decisions. Another major section of the research is devoted to the “principle of concentration of legal grounds,” whose evolution in French judicial practice—from the traditional position to the Cesareo decision and subsequent reforms—is critically analyzed. The study also evaluates the criticisms directed against this principle, its positive and negative implications, and the modifications introduced through judicial practice. Furthermore, the compatibility of this principle with Iranian law, as well as the rule prohibiting the introduction of new claims at the appellate stage, is examined. The findings indicate that French law, through the precise regulation of formal and substantive procedural rules and the establishment of a balance between procedural efficiency and judicial fairness, provides a coherent model for comparative analysis within the Iranian procedural system.</p> https://www.jhrlp.com/index.php/jhrlp/article/download/321/368