This study about the pupils' sleep in the academy of Aix-Marseille has been realized after the observations of second cycle's teachers; they have noted a somnolence by an important number of pupils during lessons, consequence of a supposed sleep lack able to have repercussions on the scholastic success. Hearing teachers and pupils' suggestions, the authors have established a questionnaire with 20 items; this study is concerning 1,300 pupils, 15 to 20 years old, in classic, technical and agricultural high schools, both in public and private establishments. The most salient characteristic is the differences between the sleep of the scholastic period and the sleep of week end or holiday. In the future, a better knowledge of pupils' sleeping habits could be the starting point of information and prevention campaign.