This report presents the results of the process and effectiveness evaluation of the Unplugged program, led by the Association for Listening and Support in Addiction and Substance Abuse (Orléans, Loiret). This initiative is one of five promising projects selected by the Interministerial Commission for the Prevention of Addictive Behaviors (Cipca), established by Mildeca (Interministerial Mission for the Fight Against Drugs and Addictive Behaviors). It is an adaptation of the European Unplugged program (Faggiano et al., 2008) to the French context. Its objective is to prevent the use of psychoactive substances among middle school students aged 12 to 14. Its strategy relies primarily on the development of psychosocial skills and the correction of social norms during 12 sessions delivered by the teacher. We collected effectiveness indicators from a sample of 1,091 middle school students in grades 6 through 8 (12 schools, 66 classes) before and after the intervention (1 month and 3 months). We then compared psychoactive substance use (experimentation, recent use) among students participating in the program (n=491) with that of students who received no prevention intervention (n=600). Process data were collected at the end of each of the 12 sessions. The results show that the program has a protective effect on the three consumption behaviors measured (cigarette and cannabis use and binge drinking), whether regarding experimentation or recent use. The program also modifies the psychosocial variables directly targeted (attitudes, CPS, social norms). The magnitude of the effects on recent use is greater than that of the original European evaluation (Faggiano et al., 2008), which is likely due to greater fidelity in the program’s implementation in the Loiret: 83% (vs. 56%) of classes delivered the program in full, and 94% (vs. 78%) of the targeted students were reached. A dose-response relationship is also observed: the effects are greater as the amount of program delivered increases. Our study demonstrates the short-term effectiveness of the Unplugged program in the Loiret on SPA consumption and its psychosocial determinants. It should be noted that these effects appear to be greater for middle school students facing certain risk factors (parental permissiveness regarding consumption, low academic performance, disadvantaged socioeconomic environment), making Unplugged a useful prevention tool for intervening with populations exhibiting vulnerability factors and for reducing social and regional health inequalities.