Abstract : The object of this study is to analyze differences in aspirations and choice of course of study at the outset of higher education. More particularly it aims to determine if the "individual" choices, which have an impact on the construction of educational inequalities, depend on school environment. Since the diversified character of school environment is an established fact in France, the first part of this work, based on a review of the sociology of education literature, draws attention to contextual dimensions as possible factors influencing educational and vocational aspirations. This question, which has remained unexplored at this level of the educational system in France, is dealt with empirically in the second part of the study. Based on a quantitative analyse of the data of a Panel of pupils in secondary education and on an original survey, the study shows that school environment is a significant predictor of the educational aspirations of high-school pupils (probability of applying for course of study of higher education and desired length of studies). School environment significantly explains the choice of courses of study of pupils with comparable school attainment and social background. The origin of this contextual effect is twofold: the social composition of the high school and the local supply of higher education (mainly the local presence of preparatory programmes for the elite sector of ‘grandes écoles' (‘higher schools')). In many cases, the effect of school context is at least as important as the effect of social background. The “individual” preferences, located in unequal contexts, are thus tinged with the organization of the educational system.