This issue of *Tendances* presents the initial results of the French component of the HBSC (Health Behaviour in School-aged Children) survey, conducted in 41 countries and regions across the Western world. This survey is coordinated by the medical department of the Toulouse Regional Education Authority, in collaboration with and with the support of INPES and OFDT. In 2006, for the second time at the national level, it surveyed 11-, 13-, and 15-year-old students enrolled in schools in metropolitan France regarding their health behaviors and their use of psychoactive substances. The analyses presented here were conducted by the OFDT as part of the partnership established with HBSC since the 2002 survey. They concern only the use of psychoactive substances and will be supplemented by other topics in the report to be published in 2008. After presenting the prevalence of experimentation among 11- to 15-year-olds and revealing that a large proportion of adolescents have never used illicit substances, the analysis will focus on 15-year-old students, for whom the questionnaire was more detailed. Finally, several associated factors, such as perceived health status or sociability, will introduce the initial points for discussion.[author’s abstract]