Diamond in the rough

Sandrine Bonnaire rose above a childhood in the run-down Paris suburbs to an acting career that has astonished France. Angelique Chrisafis meets her
French actor Sandrine Bonnaire
Intellectual pin-up ... Sandrine Bonnaire. Photograph: Fred Dufour/AFP/Getty Images

On a hot spring day in a leafy suburb outside Paris, I'm wandering a tree-lined avenue trying to find Sandrine Bonnaire's house. A gate in a high wall opens, giving way to a garden in bloom and a grand villa. Bonnaire's husband, Guillaume Laurant, the screenwriter who co-wrote Amélie, welcomes me at the door. It could be the perfect setting for a French film. But then Bonnaire bursts down the stairs, coffee in hand, still chewing her breakfast, flinging herself on to an old sofa, puncturing any sense of grandeur.

Bonnaire is one of France's best living actors, arguably the best of her generation. Over 27 years, her dimples and wide-eyed stare have featured in 49 films (her 50th is in pre-production) and her portrayals of misfits - from the stubborn drifter in Agnes Varda's Vagabond to the illiterate housekeeper in Claude Chabrol's La Cérémonie - earned her a reputation as cinema's intellectual pin-up. However, she comes from anything but an intellectual background. Raised with her 10 siblings on a run-down estate outside Paris, Bonnaire left school at 15 after the director Maurice Pialat cast her in À Nos Amours (To Our Loves). Her performance as a loud-mouthed teenager with multiple boyfriends so astonished the critics that some feared the untrained 15-year-old would never be able to live up to it.

More than a quarter of a century later, though, she is a household name, famed for her emotional honesty on the screen and off it. Two years ago, she broke the silence in France surrounding autism, with a harrowing documentary about her sister, Sabine, showing her descent from piano-playing, high-functioning teenager to withdrawn and violent adult after being confined for five years in a psychiatric hospital where she was restrained and drugged. It had record audiences on French TV, won an award at Cannes, was shown across the world and saw her summoned by Nicolas Sarkozy to advise him on new plans for autism care.

Now Bonnaire is back in front of the camera in Mark of an Angel (L'Empreinte de l'Ange), an understated psychological thriller about a different family trauma: babies swapped at birth and brought up by the wrong parents. The film was inspired by a 2003 US news story about parents who realised their 10-year-old daughter had been switched on a maternity ward. But in the film, by director Safy Nebbou, the American saga has been pared down, twisted and turned on its head. A woman sees a young girl who she thinks resembles the baby she lost in a hospital fire years before. Obsessed by the likeness, she begins stalking the girl's real mother and family.

It's a subject with so much resonance in France that the same US case has already inspired a French TV film. "It's such a universal story, I suppose," says Bonnaire. "But this film is about lies: lies at the heart of a family and lying to yourself."

Bonnaire plays a bourgeois mother with a perfect home and family; Catherine Frot, better known for playing comedy until the recent thriller The Page Turner, plays the woman driven mad by grief. Bonnaire says that after years of playing outsiders and misfits, she found it difficult to play the contented wife. "Safy said, 'You're a very nice woman, happy in herself, with a good husband and a nice house.' And curiously, it was much harder to play that part than what comes afterwards in the film. I've never really played everyday people. I've played realist roles, but not mere daily life. There was always something incredible happening to my characters."

But she liked the idea of a thriller about a family. "Our family makes us who we are, defines us totally. When you go to a therapist or have analysis, whatever reason you go in for, they will always bring you back to your family. We're strong or weak according to what family we have. You might have left them long ago, might not even talk to them, but something lingers, we have no choice."

Until Bonnaire lifted the lid on a life spent caring for her younger autistic sister, she had been reluctant to talk about her own family, or her Jehovah's Witness mother. Did her childhood give her a sense of faith? "No, the only Jehovah's Witness was my mother. Even my father didn't believe in it; there was a lot of conflict between them because of that. We never believed in any of it; it annoyed us. We couldn't bear that milieu, that world, those people - to us it was awful. Me, I don't know where you find faith. I tend to say faith is believing in life, and as I love life, I try to do the best with it, make it as serene and joyous as possible. Like everyone, I guess."

Bonnaire was the sixth of 11 children, and her sister Sabine was the seventh. She made the documentary, Her Name Is Sabine (Elle S'Appelle Sabine), "to bear witness" for all the other families of autistic people in France. In it, she cuts together her old home-video footage of the beautiful, long-haired young Sabine dancing, playing the piano, going on holiday to New York, swimming in the sea and speaking English. It stands in sharp contrast to the bloated, anxious, highly medicated Sabine of today, biting her hand and lashing out. Sabine watches the old home videos and weeps what she calls "tears of joy". Her Name Is Sabine also follows her new life in a small house with carers in the French countryside. Bonnaire said she wanted to make the film because there weren't enough proper portrayals of autistic people on screen. Rain Man, she felt, did not tell the whole story. People now stop Sabine in the street, recognising her from the film. I ask how she is. "I was with her yesterday," Bonnaire says. "She's making constant progress. The film did her good, the fact that people are taking an interest in her, that she can feel useful. It's a big thing, because Sabine was always hidden, locked up in a hospital, called Crazy Sabine. And today she is accepted in the social world - people come to see her and tell her they loved the film. That has been very positive."

Bonnaire only started acting by chance at 15, when one of her sisters answered Maurice Pialat's ad for a teenager to star in À Nos Amours. She accompanied her sisters to a casting, just to watch, but was asked to do a test and, after a gruelling selection process, was chosen. "I didn't want to be an actress. It wasn't a dream. I didn't have any dreams at all. Where I came from, families didn't have money and no one could have afforded acting classes. For cinemas or museums, you had to go to Paris, which seemed really far away to us. When you're a small child there's no problem with the banlieues [high-rise suburbs] because it's like a big playground where everyone knows each other. But when you become teenagers, you realise it's a kind of ghetto: all the people on a certain income are put in one place, all the immigrants are put in another. So you feel shut away. Paris for us was like crossing a border."

Now, she says, after working with so many intellectuals, she has educated herself. "But I'm absolutely not a grand intellectual, not at all." Her Name Is Sabine has given her a taste for directing and she is writing her second screenplay, inspired by a man she knew as a child.

As for the future of French film, she says: "Our big directors are getting old now. Some have already left us, and those still here won't be here for much longer. There are some young directors who are interesting, but I honestly don't know who will be as talented as a Claude Sautet, a Claude Chabrol or a Maurice Pialat. For the moment, I can't see who could take over. The fact that cinema is now funded by television has changed things: it's more about entertainment, more comedy. From time to time, little miracles come along, like Seraphine, or La Graine et le Moulet (Couscous). And yet all the time people say, 'Oh, la la' - they're worried French film is not going to last much longer. I've been hearing that for 15 years, but we're still the country in Europe that makes the most films each year. We make more films than you, but perhaps our films don't travel as well because of the language."

With her own career, nothing was planned, she says. She never chose the astonishing roles given to her; she chose directors first. "I just wanted to work with the greats of French cinema," she says with a shrug. "And they always cast me as rather marginal girls."

Sandrine Bonnaire will join a Q&A at Ciné Lumière, London, on Monday. Mark of an Angel is released on 22 May