This contribution was aimed at examining if the privileged position of Grandes Écoles on the French labour market could be linked to training and, in particular, knowledge acquired in these courses. The REFLEX survey data allows to test this hypothesis for a sample of French graduates from Grandes Écoles and University master programmes. Our results show that actually some useful skills on the labour market are more easily acquired in Grandes Écoles. This is the case in particular of 'analytical thinking' or 'ability to command a foreign language', domains on which Grandes Écoles have heavily focused their curriculum in the 1990s. We show however that the competencies acquisition process is not unique and that professional or extra-school experiences during studies can have positive effects on the attainment of skills.