The setting up of educational systems during the 19th century also saw the establishment of a normative school format. But the desire to have the educational system take charge of global social issues via, among other things, teaching cross-disciplinary topics in courses entitled, in French, “éducation à”, is seeing tendencies towards putting this format in question  These topics raise epistemological issues regarding the different academic disciplines, because they are no longer based on a reference to a scientific discipline, but on a reference reference to a dominant theme (the environment, health, sustainable development, cultural heritage…), and give values a wide space. This paper looks at several curricular studies based on the formal or the informal sectors’ offerings and focuses on showing how these “éducation à” courses partake of curricular hybridation through co-construction between formal and informal education, put into question a certain number of didactic foundations, and raise several sorts of issues of legitimacy, with a risk of ideological drift.