Debates about school in francophone countries turn around “instruction” and “education”. Condorcet’s statement „L'éducation publique doit se borner à l'instruction“ is a founding principle: school has not to “éduquer”, i.e. to transform the persons’ beliefs and moral, but to “instruire”, i.e. to give access to the principles and elements based on reason in order to “embrace all human knowledge; it’s the large basis on which relays the whole edifice of human culture” (Buisson, 1887). Instruction allows everybody to become a free person, able to decide about life, contradictory opinions and political positions: a way of defining Bildung without using the word. School disciplines and their didactics are the means to give progressive access to human knowledge. This is an abstract model. Concretely, political, religious and State power influences school contents; economic pressures want school to become immediately useful for qualifying work force. This contradiction between instruction and education lasts since long time: some defend school disciplines as they were 150 years ago; others doubt about usefulness of disciplines and promote school for life. Subject didactics as disciplinary field, on Condorcet’s line, position themselves in between: disciplines are necessary but have to be adapted since students and their environment have changed.