Director Laurent Cantet's film -- based on French writer Francois Begaudeau's experiences as a middle school teacher, was the first French film to take the Palme d'Or since 1987, when the prize went to "Under Satan's Sun."
The Grand Prix, for the runner-up, was given to "Gomorrah," Italian director Matteo Garrone's take on organized crime in Naples.
The top directing prize went to Nuri Bilge Ceylan of Turkey for "Three Monkeys."
Paolo Sorrentino's "Il Divo" won the jury prize.
Benicio Del Toro won the best actor award for his performance in the title role of "Che," and the top actress prize went to Sandra Corveloni of Brazil for her work in "Linha de passe" as a pregnant single mother of four boys in the slums of Sao Paulo.
Jean-Pierre and Luc Dardenne won for best screenplay prize for "Lorna's Silence."