Instead of celebrating April Fool's Day, in France today is called Poisson d'Avril. The word "poisson" means "fish" and people will try to stick a paper fish onto the backs of their friends. Once the joke is discovered, they will shout, "Poisson d'Avril!"
Well...below is photo evidence that the 7th grade French class paid attention during French holiday presentations..and they fooled their teacher ;) Quelle blague!