The aim of this article is to identify the consequences of the stream followed in high school on the professional opportunities of baccalaureate holders at the beginning of their career. By combining the 1995 panel of secondary level pupils with the survey on entry into adult life, we are able to identify the effects that grouping pupils by track at secondary level has on the early stages of their professional careers. This rich database allows us to account for this grouping of different students in different streams. A mediation analysis makes it possible to estimate the extent of the divergence in trajectories according to the stream, whether or not the baccalaureate holders continued their studies. The results highlight the importance of taking into account the characteristics of students prior to orientation when comparing the early career opportunities of baccalaureate holders. Mediation analysis also allows us to identify a complex dynamic between academic skills and levels of qualification, which tends to partially conceal inequalities between women and men at the beginning of their careers, whereas the track of the baccalaureate obtained tends to explain them.