There’s an extraordinary moment in Laurent Cantet’s Cannes Palme d’Or winnner The Class. An angry teacher (played by writer and former teacher François Bégaudeau) confronts a pair of gossiping pupils in the school yard. Almost immediately he is surrounded by a heated throng of voluble kids, each with their own grudge to express.

The delicate balance of power between one adult and the mercurial, many-headed creature that is a class of teenagers has tipped. The children who have enjoyed testing the elasticity of his authority throughout the school year have begun to realise their own power. The teacher suddenly finds himself under attack. He has no choice but to stalk away from the confrontation.

It’s a brilliant scene because it highlights the precarious nature of the pact between teacher and students and because, in a film with little conventional narrative, it has a potent drama and explosive energy that many thrillers can’t hope to achieve. It’s particularly remarkable given that all of the actors on screen – including Bégaudeau – are non-professional.

Bégaudeau, who was a teacher for nine years and on whose nonfiction book about a year in an inner-city Parisian school the film is based, argues that the quality of the performances is down to the skill of the director. Now a writer of, among other things, film reviews, he pulls no punches with a damning comparison between Laurent Cantet and Christophe Barratier, the director of the mawkish French hit Les Choristes. “The reason that the kids give good performances in films by people like Laurent Cantet and the Dardennes brothers is that they are good directors, they are observers of people. The acting is not so good in Les Choristes because Barratier is not a good director. Children are naturally good actors and anyone who says otherwise is wrong.”

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A slim, boyish-looking 36-year-old, Bégaudeau is given to much extravagant flapping of hands and face-pulling to punctuate a stream of French that sounds like it was fired out of a machine-gun. His quick conversational wit and repartee clearly made him an engaging teacher; they also make him a charismatic choice to play the teacher François in the film inspired by his book, Entre les murs. “We tried it out over a period of about six months, and pretty soon we realised that it was going to work,” he says of the decision to step in front of the camera. “We felt confident enough that it was all going to slot into place.”

Cantet’s commitment to authenticity means that he frequently prefers to work with nonprofessional actors. The children are all students at Françoise Dolto Junior High, in Paris’s multi-cultural 20th arrondissement; the teachers in the film (except Bégaudeau) all teach there and the parents are actual parents. “We’ve talked about the nine months that we prepared the kids, but in my view three weeks would have been enough. They didn’t need to be taught how to act because they were good from the start.”

There was a script, largely adapted from the book, but the children never saw it. Cantet and Bégaud-eau knew what was needed at the end of every scene but rather than have the students recite lines, the key kids in each scene were taken aside and coached. The rest of the class was given a vague idea of what to expect and asked to improvise around the action. “About 80 per cent of what you see on screen came from the screenplay and 20 per cent from the children,” estimates Bégaudeau, although he admits that some of the film’s most memorable moments came unscripted. A young Chinese boy’s speech in class about the shame he feels for the other students for their lack of respect and discipline was completely unprompted; likewise Bégaudeau’s own surprised reaction was equally unrehearsed.

It’s not just the original film-making technique that sets this classroom drama apart from the traditional Hollywood model. Bégaudeau speculates that the film is perhaps unique in that the camera never leaves the school gates; we know nothing of the lives outside the classroom that we can’t surmise from the behaviour within it. “The title of my book was Entre les murs – within the walls – and Laurent Cantet decided to follow the same principle, not to leave the school walls. One adult, 25 children, talking. The main thing is this dialectic.”

Another departure from the clichéd model is the fact that the teacher, rather than being portrayed as an inspirational, supertutor (like Hilary Swank in Freedom Writers or Robin Williams in Dead Poets Society), is a talented but flawed individual who makes a mistake which indirectly impacts on the school life of one of the students. In a heated moment, François the teacher criticises two girls for “behaving like skanks”, a word that has far more potent connotations for the kids than he had intended it to carry.

But despite the fact that The Class is the most genuinely exciting and dynamic film to be made about education for a long time, Bégaudeau is anything but sentimental about his time as a teacher. “I only went into it to make a living. It’s a very difficult job. And if I can make a living now from what I have always been interested in – cinema, writing, literature and journalism – then I am happier to do that than to go back to teaching. I think the school system can do without me.”

The Class shows at OWE2, Oct 18, 8.30pm, and OWE1, Oct 20, 1.30pm

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