I believe it was from the 80’s or 90’s. It took place in a school where all the students wore uniforms. A poorer classmates parent dies and the kids keep it a secret from the adults, pretending that the parent is still alive. I think maybe because there’s some fear the child will be taken to an orphanage. I recall things coming to light but the film ending on this vaguely revolutionary note. Had sort of Stand By Me vibes but a little lighter. French or Belgian.