The play `Art' took Paris by storm and then became a hit from the West End to Tel Aviv. Can Yasmina Reza do it again? Naturellement, she tells E Jane Dickson
"Life," trills Yasmina Reza, "is not enough. That is why I write. To sit in front of a blank page, it is a way of confronting le vide, this hole in the middle of our existence."

You can say this kind of thing in Paris and nobody turns a hair. In the mirrored salon of the Hotel Lutetia, the waiter bangs down our cups with existential gloom. What's a coffee stain here or there, when you're trembling on the verge of nothingness? The Lutetia has sheltered generations of Left Bank philosophers airing their ideas, but it has taken Yasmina Reza to package l'intellectualisme francaise for export around the world like so much duty-free scent. Since its Paris premiere in 1994, her play Art has been translated into 30 languages and played to capacity in London, New York, Berlin, Madrid, Budapest, Moscow, Tokyo, Tel Aviv and Johannesburg. There have been sniffy noises from some critics about "coffee-table art", but the resounding consensus is that Reza has triumphantly reconciled the theatre of ideas with a good night out. Or, as Hollywood might have it (Sean Connery has been sitting on the film rights since the Paris premiere), Reza is "Sartre with a heart(re)".

"I am the only living French playwright, whose work is known and performed across the globe," says Reza, comfortably. "I don't want to seem especially modest and say that this is not because I am the best. Modesty is a pointless sham. If you consider what you have done to be nothing, why on earth would you show it to the world? That would be the worst arrogance."

Over in the corner, a group of American matrons, feet spreading in their ankle socks, are gawping reverently at Reza. From her immaculately disordered curls to the pointy toes of her exquisite embroidered mules, this tiny, emphatic woman is the very pattern of Parisian chic, so much so that you wonder at her lack of a poodle and decide that it's probably off being dyed to match the chartreuse silk of her dress. Her neat, quick manner and put-that- in-your-pipe- and-smoke-it delivery strongly recall the pert heroines of Moliere or Beaumarchais, but La Reza, you sense, has always been more diva than soubrette.

The daughter of a Russian/Persian businessman and a Hungarian violinist, Reza, 38, was born in Paris and grew up in the highly cultivated and cosmopolitan milieu of the Jewish bourgeoisie. While other girls in her class sighed for Johnny Halliday or Sacha Distel, Yasmina had Beethoven for her teenage pin-up. ("That frown. Those brows. To me he was the last word in virility.") After a sociology degree, she went on to the famous Jacques Lecoq theatre school, but quickly realised that there weren't enough leading roles to go round.

"As an actor, you can wait all your life , even if you're very, very good, for the one great part that will make your career. This was utterly impossible for me. I'm too impatient and too sensitive to time passing. As a writer, you call your own shots."

And call them she does. Her English translator, Christopher Hampton (who also translated and adapted Liaisons Dangereuses for stage and screen), famously remarked that after working with Reza he would only translate writers who were safely dead.

"I adore Christopher now, but at the beginning, I accused him of everything. I accused him of being too faithful to the words and not faithful enough to the sense. Then I changed my mind and accused him of being too faithful to the sense at the expense of style. `Betray me, betray me,' I would beg, `but give me some style!'"

Between them, they cooked up a winner, scooping an Olivier and an Evening Standard award, but still Reza was uneasy. Art, in which three old friends are brought to the edge of the abyss by an argument over a blank canvas, had been much commended in France for its subtle interplay of intellectual and emotional themes. In England, the audience looked into the abyss and laughed.

"When I accepted the Olivier award for Best Comedy, I said, `But I thought it was a tragedy', and I wasn't entirely joking. British audiences will laugh at anything, all the time they are laughing, laughing, laughing, cackling like fools. The first time I sat in a British audience, I was so upset. I thought `Oh my god, this is terrible, the actors are audible, yes, but you simply cannot hear what the play is saying.' The people around me were saying `What's the matter with you? The play is a tremendous success!' But I was really very sad. I was very afraid that the same thing would happen in New York, but the audience there is very intelligent. They laugh, yes, but they know when to stop. And they don't cough. But," says Reza, with more regret than resignation, "you cannot control the audience."

The playwright's other great fear, sweetened, she admits, by the revenue pouring in from the four corners of the earth, is that Art's massive success would label her a one-hit wonder. "It's not so bad in France, where I was already well known before Art - my very first play, Conversations Apres un Enterrement won a Moliere - but when I'm abroad, people come up to me and say, `Ooh, I just love your play', I make a point of saying `Oh really? Which one?' To me, Art is like a party dress, a very pretty and well-made piece of work, but not at all typical of my style."

Reza could have named her price for Art II on Broadway. Instead, she offered one of her earlier plays, The Unexpected Man, to the Royal Shakespeare Company. Pesky audiences aside, "London is still the dream, the mythical prize, for the playwright".

If Art was a party dress, The Unexpected Man, which transfers on 10 June to the Duchess Theatre for a limited West End run, is a good tweed suit, a sombre and distinctly mature piece for a writer not yet out of her thirties. A distinguished but disillusioned author (Michael Gambon in marvellously dyspeptic mode) finds himself sitting opposite his greatest fan (Eileen Atkins) in a train carriage. The couple do not converse until the very end of the play, yet their thoughts, revealed in a series of monologues, are intimately connected.

The Unexpected Man, which is a more revealing and reflective play than Art, was inspired by two events in Reza's life: "One of the people I have been most impressed by in my life is a Romanian writer and philosopher called Cioran. He is unjust, he is excessive, he is all the things I admire. I must have written to him a thousand times, asking for a rendezvous, and then torn up the letter, too embarrassed to send it. One day, I saw him in the street, quite near where I live, so I followed him, desperately trying to find something to say to him, but everything I came up with in my head just sounded too idiotic. I could have gone up and introduced myself to him - I was already quite well known at the time - but it never occurred to me that he might recognise me, so I just kept on stalking him, until he turned into an empty street, and it would just have been too obvious. So I went home. And I have never been more disappointed in myself. Then, shortly after, I found myself in the hairdressers, sitting next to a woman reading Elle magazine. She was reading very carefully - fashion, films, make-up, letters to the editor - everything was read with the most minute attention, until she came to a four-page article about me, which she flipped over without so much as a glance. I didn't know where to put myself. I spent the rest of the time trying to hide my face from her, in case she would see me, and know that I had seen her and aaargh! ..." Reza trails off, hot with shame at the memory.

The comedy of embarrassment is what drives The Unexpected Man, but the dominant key of the piece is a wistfulness, or as Eileen Atkins's character puts it, "a nostalgia for what has never happened".

"I have never been able to seize the moment, to get on top of time," says Reza, in the tantalised tone of someone thwarted in her search for the perfect handbag. "I'm always either looking forward to the next thing, or looking back on the past. Time is my obsession, my infirmity, an old wound that plagues me."

For Reza, who has a daughter and a son by the film-maker Didier Martin, motherhood has made her obsession even more acute: "Having children is a very strange experiment in time," she says. "You never see yourself or your friends, or even your parents growing older. But children are changing every day. Every day, you see moments you will never, ever see again. You can only look at them as you would look at a landscape out of the window of a train; you try to focus on a feature of the land, but already it's slipping away from you. My daughter is 10 now, and I keep saying to her, `Stay like that! I love you like that!' But soon she will be 12, and that is no longer really a child. Soon she will lose this smile that I love, this fabulous, frank smile that has no thought of seduction."

Seduction, you sense, is not a means to an end for Reza, but rather a way of life. "I am very, very, very feminine," she avers. "Women are in France. With some women," she says, naming no names, "there has been some, shall we say, confusion, between ideas and appearance. But I have always been impervious to such ideas. I consider feminism to be quite appropriate in social matters, but ... mais enfin, ca suffit!"

Certainly, she is not about to rehearse the usual lament about combining creative work with home life and children. "It's easy," she says, with an abracadabra smile. "The more I have to annoy me, the better I work!" She regrets however, that even in France, "one cannot pose for Vogue and be treated like a serious woman of letters".

"I have always played the glamour card to the full," she says, happily. "I much prefer to open the pages of Vogue or Elle or Marie Claire and see myself looking ravishing, than appearing in some learned journal, endlessly spinning out ideas. It is not the job of the writer, or the playwright to have ideas, but to interpret the world in front of them."

Reza's refusal to provide scholarly commentaries on her work is indeed a courageous stance in France, where the worth of a book or play is measured by the amount of analyses du texte it spawns. But Reza is not to be swayed.

"As a writer, you weigh your words, you spend time looking for exactly the words you need in your work. Why would you then use other, less carefully weighed words, to discuss them? It is a nonsense, a kind of ego trap for authors. I'm always being told that the image I present in magazines is just a mask, nothing to do with the real me. Well, of course it is! That's why I do it. Why on earth would I serve myself, my real self, up in a magazine article?"

There is no easy answer to this, but Reza pulls herself back from the brink with one last, titanium flash of charm.

"The truth is," she says, showing empty hands, "I have nothing to say"