Abstract
Based on a research into the disparities in access to preparatory classes for entrance to the grandes écoles, we will analyze how teachers involve themselves in teaching activities and respond in varied forms to the simultaneous requirements of justice and efficiency. Findings show how teachers adapt to the broadened student intake on the one hand and to the diversified courses provided in preparatory classes on the other hand. Subject-based teaching, curriculum requirements, and teacherstudent relationships legitimate teachers’professional activity and are behind new teachers’professionality.