Data from the 2010 Health Behaviour in School-aged Children (HBSC) survey show a significant decrease in sleep duration among middle school students in France. Specifically, 15-year-olds sleep an average of one and a half hours less per day than 11-year-olds. The most striking trend involves the proportion of “light sleepers” (less than seven hours per night), which increases significantly during adolescence, affecting nearly one in five students in 9th grade.