Film: Boring? Irritating? Surly? Moi?

The hotel is tucked away discreetly behind a high wall down a grey, treeless Parisian street full of pearls and poodles. Through the marble portal there's a book-lined bar, which looks as though its library was bought by the ton rather than the title. Someone is smoking a stinking cigar. "It smells a little English don't you think?" says Juliette Binoche.

Binoche is one of those film stars famous enough not to need to dress up for such five-star surroundings. Despite being among France's highest paid citizens, the 35-year-old actress is wearing leggings and a baggy old blue jumper. Her signature black bob has grown long and is scraped into a ponytail. The pale face with its high cheekbones and button-black eyes wears no make-up and her retrousse nose is a little red. Her legs are planted wideapart to make room for her big belly.

Binoche is expecting her second child but the name of the father, like much of her personal life, is off-limits. A "tiger" when it comes to her privacy, Binoche has a reputation for being "difficult" with journalists. She has compared the press to a form of "pollution" and often sits through interviews in a monosyllabic sulk. In her late twenties she gave up doing interviews altogether for a few years, but when that move was "misinterpreted", she found the "humility" to "do her duty."

Such Garbo-like reticence sits well with the star's screen image. In films from Les Amants du Pont Neuf to The Unbearable Lightness of Being and Three Colours: Blue, Binoche has combined solemnity with sexuality and tranquillity with a child-like spontaneity. Suffering is her speciality. Among the emotionally-damaged characters she has assayed are an artist going blind, a grieving widow and a self-destructive adulteress: what Binoche calls her "sorrowful sisters". Even in 1995's sumptuous costume drama The Horseman on the Roof, Binoche was galloping through a France rotten with cholera.

Although she's "too fat" to be photographed, Binoche is being tres agreeable today. She speaks good English (with a strong inflection of Californian psychobabble) and rattles away about Life and Art, interspersing her cod philosophy with roars of laughter. Her hand keeps rubbing her stomach absent-mindedly and squirreling away complimentary nuts from a silver saucer. Nothing about her seems tragic or sad, doesn't she ever long to shake off the mantle of the martyr?

"It's funny because that's not my feeling at all. The characters I'm playing go through a lot of things. Otherwise why should I play these parts? I wouldn't waste my time brooding in everything. I'm not that kind of person. Films are like life: there are moments of comedy and moments of tragedy. I think even in Blue there's a moment where she's laughing about some story just before she dies."

A theatre director and actress, Binoche's parents divorced when she was four years old. She was sent to boarding school, which she hated. "Now that I'm more conscious of what happened in my childhood, I sometimes wonder how I survived. As a child I think we have suitcases of happiness without knowing where they come from." Unpacking her own emotional baggage in the playground, Binoche began "play acting" between lessons. Later, she would stage productions of Moliere and Ionesco, cross-dressing to play the male leads.

After school, Binoche went to the Paris Conservatoire. Dropping out after a year, she got her first role in 1982, followed by small parts in Jean- Luc Godard's Hail Mary and Annick Lanoe's Les Nanas, a "post-feminist" update of George Cukor's The Women. Despite rollerskating through the latter in hotpants, she was already cast as the lovelorn gamine. Her first leading role came in Andre Techine's Rendezvous. Fourteen years later, still resolutely anti-Hollywood (she's turned down roles in Jurassic Park, Raiders of the Lost Ark and Schindler's List -European directors, she argues, "have more to say") Binoche is working with Techine once again on his new film.

A sprawling, Freudian family melodrama, Alice et Martin sees Binoche's neurotic free spirit falling for her flatmate's much younger, mentally- ill brother. By the end of the film Binoche has gone from chain-smoking violinist to pregnant, maternal carer.

"I think she becomes responsible" says Binoche. "At the beginning she has a lack of gravity. There's nothing to tie her to the earth. She's free, but she's lost. It's like a butterfly that goes on a window and doesn't know where to go."

Does she believe that freedom and love are contradictory? "I think there are different ways of loving and of involving yourself in a relationship. At the end of the film there's a purpose in their relationship, because a child is coming. It's not just a closed relationship between two people. They have to look in the same direction and not into each others eyes any more, so maybe it's freeing in a way."

The parallels between Binoche and Alice are irresistible. With one young son from a previous relationship and another baby due in January, Binoche is presently in a relationship with Benoit Magimel, 12 years her junior. Becoming a mother, she says, has made her keen "to stay in one place to give her children some equilibrium". Like Alice, Binoche seems to have grown-up. "Before Rendezvous I was a tomboy. I think it was a way of protecting myself from a man's world. Even though I was feminine, I didn't want to play the coquette, I wanted to play it straight."

I tell Binoche that Leos Carax, the wild-child director with whom she had a four-year relationship, and a famously troubled three-year shoot on Les Amants credits himself with showing the boyish Binoche that she was a "beautiful woman." She frowns. "It was more me saying that, than him saying that. Maybe he took what I was feeling... '

Tomboy she may be no longer, but in her latest film Binoche gets to satisfy her schoolgirl passion for cross-dressing. Directed by Diane Kurys, Les Enfants du Siecle is the story of George Sand and precocious author Alfred de Musset (played by Magimel). As "a female actor with children - independent" Binoche says she felt "very close" to her subject. Then there's Unknown Code, a movie tailor-made for Binoche by Austrian director Michael Haneke. "I'm playing an actress, as she is perceived by a man. As she's perceived by a director. As she's perceived by Michael, anyway. I'm kidding! Michael has had a lot of relationships with actresses so he thinks he knows about them. I said to him, `you should give me their numbers. We can talk'."

And with that, the robustly unmysterious Miss Binoche wolfs down the last of the nuts, lets out a big laugh and slips off into that other world, the one where she's always the tragic femme fatale.

`Alice et Martin' is released 3 December