The study is based on the analysis of previous French legislation, on drafts and legal documents which led up to the law, and on interviews with the legislators involved. Part I analyzes the political forces and the political manoeuvering which resulted in the criminalization of drug use. Part II shows that many of the involved politicians knew that the criminalization would not solve the problems of drug use which had emerged in the 1960's; however, they felt the need to legislate to satisfy the demands of the alarmed French population. Part III focuses on why and how several attempts to modify the drug law since then have failed. The appendix uses the evolution of the law of December 31, 1970 to develop a sociological approach and study method to the criminalization of other behaviors. Bibliographical references