The aim of this study was to make a first comparative approach to teenagers' consumption of psychoactive substances within samples drawn in France and in Brazzaville the Congo. The samples consisted of 1637 French high-school students and 155 Congolese students. An anonymous questionnaire with 13 closed items was completed. Whilst 82.1% of the male and 74.5% of the female French students had already consumed some alcoholic drinks, only 42.4% of the male and 44.0% of female Congolese students had consumed alcohol. French high school students were more affected by tobacco addiction: 22.2% (male) and 22.9% (female) of the French students smoked daily; only 3.0% (male) and 1.9% (female) Congo-lese students were smokers. The consumption of psychotropic medicines (sedatives, anxiolytics or hypnotics) appeared overall to be less among French high school students than the Congolese, particularly in boys (11.9% versus 17.2%). This consumption was mainly from medicine taken without medical prescription or misused. The use of cannabis appeared overall to be higher among French high school students (45.9% of males and 31.6% of females) than the Congolese (12.5% of males and 7.4% of females).