In the Occitanie region, a tobacco prevention program—which involves young peers trained to raise awareness among their peers—succeeded in preventing an increase in the prevalence of daily smoking among the group that received the peer intervention. After two years of the project, the evaluation shows a significant difference of 9.6% in daily smokers between high school students in the intervention group and those in the control group. Given these encouraging results, the program has been expanded to two other regions. Florence Cousson-Gélie analyzes the motivations, social norms, and the influence of peers and the family environment on smoking initiation and consumption. Furthermore, to prevent middle school students from taking up smoking, they must be helped to develop their psychosocial skills: gaining confidence and self-esteem, and learning to resist peer pressure.