Politicians' spouses are expected to look the part

It has started: just a few days after François Hollande ousted Nicolas Sarkozy as France's new president, the fashion press are already rushing to praise his partner, the political journalist Valérie Trierweiler, for her style, describing it as chic, understated and the "antithesis of bling".

How long will it be before she is castigated for not promoting French designers, and compared with the ever-chic Michelle Obama on state occasions?

Disappointingly for those excitable fashionistas, she claims to have no interest in cutting a glamorous figure, Carla Bruni-Sarkozy-style, saying in an interview: "What I'm scared of is losing my identity. I am not seeking notoriety and I am not seeking to grab the limelight."

Nevertheless, she may have little choice about being measured against her predecessor but, perhaps, with the current socialist mood in France and the contempt many felt for the former supermodel and singer, her simple style will not be found wanting.

The fashion world may have thrilled at Bruni-Sarkozy's beautifully tailored Dior suits, ballet pumps and handbags when she accompanied her husband abroad, but by the end of their time at the Elysée Palace she was dressing down; pundits attributed this not to her recent childbirth but to a calculated attempt to reconnect with disillusioned voters. "We're modest people," the multi-millionairess told the French newspaper Le Monde, to much derision.

Treirweiler, on the other hand, claims to buy her simple black suits, white shirts, trench coats and scarves at the market. That's the definition of austerity chic.

Poor Bruni. Not since Jackie Kennedy has a politician's consort inspired such sartorial scrutiny, but she made no attempt to disassociate her image from the US's most famous first lady, wearing pillbox hats, boxy suits and chic up-dos that explicitly linked her with the much-loved wife of JFK.

Unfortunately for her, she has almost as often been compared with Marie Antoinette for her - and her husband's - extravagance. Shortly after her marriage, she posed for an Annie Leibowitz shoot in Vanity Fair, in front of the tapestries at the Elysée Palace, wearing jodhpurs and riding boots, with the headline "Carla Bruni: the New Jackie O?"

It didn't help that just under a year after their marriage, Michelle Obama came on to the scene, gathering praise everywhere she went for her approachable, fashionable style.

Held up against Cindy McCain, the wife of John McCain, who preferred a more decorous style - all Oscar de la Renta dresses and patrician polo necks - Obama's customary J Crew high-street pieces, with dips into the creations of young American designers such as Thakoon and Jason Wu, were relaxed and appealing.

She wore the clothes, rather than the other way round, and dressed as exactly what she was: a hard-working mother and highly intelligent Princeton graduate, rather than a pretty piece of arm sweets for Barack Obama.

Of course, that didn't stop the comparisons when Mobama and Carla met in person, and the state fashion obsession spread from the Ukrainian former prime minister Yulia Tymoshenko and America's secretary of state Hillary Clinton to the British prime minister's wife Samantha Cameron - a natural target, given her previous job as the creative director at the chic leather-goods brand Smythson of Bond Street.

Dressing the part has become, during the past four years, as much about national economic duty asetiquette, with even those women who attempt to retain their independence, such as Laureen Harper, the wife of Canada's PM Stephen Harper, and Sarah Brown, the happily dowdy wife of the former British PM Gordon Brown, being strong-armed into supporting their respective national fashion industries. Luckily for all of them, the Duchess of Cambridge came along to take some of the pressure off.

As for Trierweiler, she knows the media game, thanks to her time working for Paris Match. But while she might be not be interested in competing with other wives of politicians, there is one woman to whom she will find herself compared whether she likes it or not: Ségolène Royal.

The former Socialist presidential candidate has a lot in common with Trierweiler - the good Gallic bone structure, the effortlessly stylish blow-dry, the simple Parisian style. Oh, and until 2007, Royal was the long-term partner of one François Hollande. With a history like that, no one's going to care about the shoes.