Over the last 45 years, two major trends have characterised French educational policies: a voluntary move towards widening access to upper secondary school and a related diversification of the diplomas available at the end of it, especially through the creation of the technological "baccalaureat" in 1968 and the vocational "baccalaureat" in 1985. In the context of educational expansion, to what extent are these successive reforms of upper secondary education curriculum associated with changes in classed and gendered trajectories through the system? Our empirical evidence is derived from four large-scale longitudinal surveys, which have never been analysed together yet: the 1962-1972 INED survey (N = 15,154), 1980-1990 Panel study (N = 19,701), 1989-2001 Panel study (N = 20,524) and 1995-2006 Panel study (N = 17,157). We use advanced log-linear and log-multiplicative models on contingency tables. We find that, when "baccalaureat" is measured as a dichotomy between holders and non-holders, class inequality has decreased since the 1960s. However, when subtler differentiations between "baccalaureat" types are taken into account, the strength of class inequality is shown to be constant over time, supporting Lucas's (2001) "Effectively Maintained Inequality" hypothesis. Further results related to change in the pattern of inequality at the "baccalaureat" level, especially gendered class inequality, are also presented and discussed. (Contains 11 notes, 5 figures, and 6 tables.)