Introduction. The article examines how the legal mechanism of preliminary investigation operates in France, taking into account the special approach of the French public authorities to its implementation, the importance of preliminary investigation in the criminal process of this state. And also, taking into account the fact that there is no institution of preliminary investigation in the Russian judicial system – such an investigation is carried out, according to domestic legislation, by investigators of the Investigative Committee of the Russian Federation – the procedural status of investigative judges of France, who belong to the judiciary on a permanent basis. Materials and methods. The research methods are a system of specially scientific and philosophical worldview approaches that provide an opportunity for an objective analysis of the topic. The research applied such methods as comparative law, historical law, formal law, structural and functional, as well as dialectical and materialistic Materials and methods. The research methods are a system of specially scientific and worldview approaches that provide an opportunity for an objective analysis of the topic. The research applied such methods as comparative law, historical law, formal law, structural and functional, as well as dialectical and materialistic. Special attention is paid to the problem of determining the role of the preliminary investigation in legal proceedings, the characteristics of its judicial status in the exercise of powers by the relevant attention is paid to the problem of determining the role of the preliminary investigation in legal proceedings, the characteristics of its judicial status in the exercise of powers by the relevant state authorities in science: the works of such scientists as M.V. Aleynikov, A.N. Volchanskaya, A.E. Vorobyov, B.Ya. Gavrilov, V.N. Galuzo, A.V. Grinenko have been published on this topic, L.V. Golovko, K.F. Gutsenko, S.A. Danilyan, I.S. Dikarev, A.Yu. Zotov, N.A. Kanafin, A.N. Konshakov, I.Ya. Foynitsky, M.Yu. Fisakov, etc.Research results. The purpose of this study is to conduct a comparative legal analysis of the preliminary investigation carried out by the relevant public authorities in France, with a comparative comparison of the role of the preliminary investigation carried out by public authorities in this State. In order to achieve this goal, special attention in this work will be paid to solving the following tasks: to identify the place of authority for the preliminary investigation in the activities of various law enforcement agencies; to investigate the features of the preliminary investigation at different stages of the development of France; to establish the features of its transformation; to analyze the real role of the preliminary investigation in France and characterize the authorities exercising authority to conduct it; to make a generalizing conclusion about whether it is advisable to make changes to the definition of the place of the preliminary investigation in the judicial proceedings of the Russian Federation, taking into account the legislative experience of France.Discussion and conclusion. After the Introduction, the article examines the very Concept of "preliminary investigation" and its national characteristics; The activities of judicial bodies conducting preliminary investigation; The procedure for conducting preliminary investigation; The end of the preliminary investigation; Instance control over the activities of the investigating judge. In conclusion, the authors of the article propose some theoretical generalizations on this topic and show the most outstanding distinctive features of French legislation on preliminary investigation in terms of methods of legal technique.