Marie Antoinette (12A) <!-- none onestar twostar threestar fourstar fivestar -->

Lost in dissipation

It's quite an irony that the one thing everyone knows about Marie Antoinette - her famous dismissal of the French peasantry, "Let them eat cake" - is condemned as apocryphal in Sofia Coppola's portrait of the lady. For this movie serves up one glistening slice of cake after another, an experience so rich and cloying that by the end you may feel that you've just cleared the whole pudding trolley.

At one point, someone whispers of the teenage princess that she looks "like a little piece of cake", and in case we don't pick up the motif, there are frequent shots of fruit tarts and various fancies arranged in tableaux of glazed abundance.

And if it's not cake, it's clothes. Marie Antoinette could rival The Devil Wears Prada as the year's most fetishistically detailed tribute to high fashion: the court at Versailles turns out to be quite as obsessive in matters of hemlines and waistlines as the enclaves of haute Manhattan 200 years later. The 14-year-old Austrian princess Marie Antoinette (Kirsten Dunst) no sooner sets foot on French soil than she is fallen upon by a team of maids, stripped of every Viennese stitch and recostumed, like a living Barbie, in the raiment of a French royal. Even her beloved pug is plucked from her arms: "You can have as many French dogs as you like," she is brusquely informed.

She has been sent to Versailles as the bride in an arranged marriage to the teenage Dauphin, Louis (Jason Schwartzman), a union designed to consolidate amity between the two nations.

Yet Coppola is working on a more ambitious canvas here, and any expectations of a conventional period biopic are swiftly quashed by the hot-pink-on-black opening credits and the unmistakeable metalled chords of postpunk favourites Gang of Four. The rest of the soundtrack is equally anachronistic, and hearing the likes of Bow Wow Wow, Adam and The Ants, New Order and Siouxsie and the Banshees sent me right back to an age of school discos circa 1979-81. It was good to hear them again, but I'm not sure that the images and music make a good fit. The sophistication of a Parisian masked ball is not enhanced, for example, by the melodic silliness of "Hong Kong Garden" blaring over the top. The fusion of English pop and French dance is all a bit Moulin Rouge!, though happily there's no Ewan McGregor to ruin the songs for us.

Less confident with words than she is with music and design, Coppola wants to rescue her heroine from the spoilt, contemptuous madam that history has handed down to us. She sees Marie Antoinette as a sweetly affectionate and innocent young girl thrust into a hothouse atmosphere of intrigue and gossip for which she has no aptitude. Along with her Austrian habiliments she is also robbed of her privacy: from the moment she wakes up she is surrounded by a gaggle of flunkeys and valets to dress her, feed her, mind her.

Even on her wedding night, she and Louis climb into bed under the beady gaze of their court, while a cardinal intones his blessing on the marital couch. Much good it does them: Louis, plump and self-absorbed, proves happier riding to hounds than to his wife's needs.

The film devotes much scrutiny to the ins and outs, as it were, of ceremonial gravitas, and displays a real fascination with how the clogged opulence of Versailles might affect an impressionable young woman. To say that this isn't very gripping would be to mistake Coppola's modus operandi as a film-maker. She doesn't want to "grip" anyone; her priorities are to do with nuance of mood and intricacy of observation, much as they were in her debut The Virgin Suicides and her breakout second movie Lost in Translation. She likes to establish a sense of place, be it a sleek Tokyo hotel or a French pleasure palace, and then hang around to see what happens next.

The problem here is that nothing happens next. There are distant stirrings of disquiet from the capital, followed by the hard news of revolution, yet the political world remains almost entirely off-stage, much as Watteau excluded it from his picnic paintings of the French aristocracy. Coppola belatedly gestures towards the popular animus via stylised placards denouncing the spendthrift queen as "Madame Deficit", but she seems as little interested in the national perception of Marie Antoinette as the woman herself was.

This wouldn't necessarily matter if there was something to hold the centre, in the way Bill Murray's sorrowful majesty filled out the wispy structure of Lost in Translation. Alas, Dunst has the trappings of majesty and very little else: she's a charming featherweight with a lovely slow smile, but quite empty of wit or reflection.

Perhaps this would be credible in a sheltered teenage princess. But Marie Antoinette purports to cover 20 years of its subject's life, so it would be reasonable to expect that motherhood or her later affair with a Swedish prince might effect some change in her. The evidence is scant.

At the margins, Steve Coogan and Danny Huston provide brief dashes of fun, and Judy Davis as an etiquette sadist invests fresh meaning in the word "uptight". The unseen star is the costume designer Milena Canonero, in whom Coppola found a very sympathetic collaborator: "When I first met with Sofia, she had already been doing several months of research in France and told me her ideas about the macaroon colours - the bold pinks, the gold yellows, the pistachio greens," Canonero says.

Well, let us allow that the macaroons are sensational. Coppola herself has been a muse to the New York designer Marc Jacobs, so she has double the reason to know whereof she speaks: where would you find a greater assembly of hairdressers, wardrobe consultants, personal assistants and general hangers-on than the world of fashion? Answer: the movies. Marie Antoinette is about confinement in a gilded cage, and, perversely or not, shows itself far more interested in the cage than in the prisoner.