A riddle named Deneuve

Such early international success (Deneuve was 24) was all the more extraordinary for a woman who, though the daughter of actors, had had no training, and for most of her life had been overshadowed by her sister, the radiant and vivacious Françoise Dorléac. But Roger Vadim, the film director who picked Catherine up when she was 17 and still a brunette, saw her potential: "Her delicate nose, her intense but slightly cold expression, her mouth with the finely drawn lips, so classically perfect that they concealed deep sensuality, were the very image of romantic beauty."

Soon after Deneuve completed Les Demoiselles, in which she co-starred with her beloved sister, Dorléac's car skidded off the motorway, overturned, and went up in flames. She was burnt alive. Deneuve, true to her ice-queen persona, said that she didn't have time to grieve because she was working on a film, but later revealed that, nearly 20 years after her sister's death, she had collapsed with the weight of what she had repressed for so long.

"I hate effort," Deneuve has said. "Or, rather, I hate it to show." Her coolness, her composure led critics of her early films to say that she couldn't act, but she gradually won respect. Yet, just as her screen persona has showed that she can be all things to all men, the quality of her acting has varied with that of her directors and screenwriters: she doesn't rise above her material. In a formulaic film, such as Robert Aldrich's Hustle (1975), her hauteur is uninflected, and she seems merely bored. But directors such as Buñuel, with Belle de Jour and Tristana (1970), or François Truffaut, in La Sirène du Mississippi (1969) and Le Dernier Métro (1980), have brought out her impishness and maternal warmth.

With The Hunger (1983), Deneuve even became an object of desire to some women: playing a role that was, in a sense, an amusing take-off on her image, she was an ageless beauty who remained so by sucking mortals' blood. In bed with Susan Sarandon, she devoured her prey erotically before biting her neck. Asked about her own desires for women, Deneuve said only: "I love vampire movies."

But, in the larger sense, is Deneuve a Good Thing for women? Marriage, she has said, is obsolete and a trap; she was married (from 1965 to 1972) to David Bailey, but earlier had a son with Vadim and later a daughter with Marcello Mastroianni, without marrying either man. Her reserve was welcome in the decades when open-mouthed expressiveness, at the expense of dignity and grace, was the norm, and, although she has appeared in films as the plaything of men, she has, for the most part, like the prostitute of Belle de Jour, remained spiritually untouchable. But is this a real triumph? When his victim is indestructible, the man escapes guilt, and is free to debase again and again.

Indeed, Deneuve, despite insisting on the importance of independence, is often a glorification of the woman who, as a "sensible" wife, trades her looks for status and money, her marriage a ballet of alternating passion and disdain. Deneuve's rise in the Sixties paralleled the embourgeoisement of both the real and the ideal Frenchwoman. No longer a blowzy peasant or saucy shopgirl who faithfully used a bidet but never a bathtub, the French dream woman didn't smell of hairy armpits but - like Deneuve - of Chanel. As groomed as she was beautiful, dressed by Saint Laurent, Deneuve, as she entered middle age, sailed along, invulnerable to age and fashion.

Deneuve came to represent not only her countrywomen but France itself. In Le Dernier Métro, she portrayed an honourable, quietly defiant Parisian under Occupation; in Indochine (1992) she exemplified colonial good intentions. By then, Deneuve's identification with her country had been set in stone: from 1985 to 2000, she was the model for the Marianne bust, the official symbol of France.

Just as Deneuve has entered French people's idea of their identity, so has she troubled ours. Much as we might dislike the notion that the French have of their superiority, when we look at this smiling sphinx, it's hard not to think that they may be right.

The National Film Theatre Catherine Deneuve retrospective runs 1-28 September (020-7928 3232)