Note that I teach in a French web school where students do work on real projects from real clients, for free, in year 2 and 3. In another web school where I teach at 'master level', year 5, the project are real paid projects for real clients.

It's totally possible, and I must say, it's even the rising ideology that you have to make students work on "real projects" (with wildly varying definition of what that means); so yes, it's a little bit crazy to see young students working 3 years 15 hours a day on arbitrary exercises, and calling it a school that will produce wildly creative professionals.

French unions have no say in the curriculum of a private school (and it would make absolutely no sense, lot of fantams about french unions there I think!).

Private school can teach pretty much what they want. If they want they diploma recognised by the government then they must comply to some policies of the ministry of education, but it is up to them.