When he set out to direct “The Class,” a dramatic look at modern French society through the prism of an urban middle school, Laurent Cantet knew at least one thing: He didn’t want to make another “Dead Poets Society.”

“The teacher in ‘Dead Poets Society’ never makes a mistake,” he says. “We wanted to show a teacher who is always improvising, always negotiating and always making mistakes.”

That teacher, Francois (played by teacher-turned-thesp Francois Begaudeau, whose novel “Entre les murs” inspired the film), is a charismatic free-thinker who seeks to energize and challenge his students through informal, impassioned discussion.

Cantet encouraged a similar spirit of participation among his cast of young non-professionals, all of whom were students at Francoise Dolto Junior High, located in Paris’ diverse 20th arrondissement, when the helmer and his crew showed up to start auditioning in November 2006. Unlike the fictional Francois, Cantet had no trouble managing and working with 20-odd adolescents.

“They’re not used to adults listening to them and giving them this kind of attention. I think they were very, very impressed by that,” Cantet says.

Though the actors were encouraged to improvise, Cantet and co-scribes Robin Campillo and Begaudeau conceived the project with distinct characters in mind. Esmeralda Ouertani, as an irrepressible chatterbox not afraid to put her teacher in his place, was essentially playing herself; soft-spoken Franck Keita, however, couldn’t have been more different from the rebellious, disruptive teen he was asked to play.

When Cantet won the Palme d’Or at Cannes in May, he was joined onstage by his young actors, some cheering enthusiastically, some making peace signs — a rare and bracing spectacle at a film festival that often favors the difficult and the obscure.

“In France, and I think all over the world, young people are judged very, very badly. Everybody is a little bit afraid of them — afraid of their vitality, maybe,” Cantet says. “I wanted to show them as a group of valuable people who can think, listen, learn to live together.”

Recent breakthrough: “This film really helped me find a method of working that I’ve been looking for — multiple cameras, and this way of mixing improvisation and direction.”

Role model: “The first person who comes to mind would be (Roberto) Rossellini. It’s difficult to have such a model.”

Next project: “I won’t have time before February or March to think of anything else.”