High above the Paris rooftops, in an exclusive restaurant called Kong, three girls are showing off their underwear.
It is the launch of the new line of lingerie from the popular French brand Lou. The guests are fashion trade press journalists - and one flushed Campaign correspondent. After the show I chat to Jerome Giachino, the marketing manager of VF International Intimates - the company that distributes Lou and its sister brand, Bolero. He's the reason I'm here.
Bolero recently got into trouble for a poster featuring a young woman pulling down a pair of shorts to reveal a thong - or "string", en francais - printed with a tiny astrological sign. The girl wore a seductive smile and the tagline read: "Je suis vierge - et vous?" ("I'm a virgin, how about you?" In French, the words for virgin and Virgo are the same).
Suddenly the media was full of denunciations of the ad industry and the way it represented women. The Bureau de la Verification de la Publicite - the French Advertising Standards Authority - warned agencies to tone down the sexual innuendo. And the crusading minister for citizens' rights and workplace equality, Nicole Ameline, promised to push for tighter legislation.
At the start of February, she produced a co-signed declaration with the BVP president, Jean-Pierre Teyssier, in which the organisation promised to watch for offensive material with "increased vigilance". Ameline has also launched a telephone and e-mail hotline encouraging women to give their opinions on the subject. The survey results will be announced in March.
All this was unexpected in a country famed for its laissez-faire attitude to sexual imagery. Indeed, the arrival of eye-popping lingerie ads on French billboards just before Valentine's Day is something of a tradition. The problem is that they have become increasingly daring.
Giachino says he was surprised by the fuss over the Bolero ad (created by the Barcelona agency Valverde de Miguel). "Bolero has been around since the 50s, and it has always had the same positioning. The Bolero girl knows she is seductive and isn't afraid to show it. If anything, she is a powerful, liberated figure."
He admits that the "Je suis vierge ..." poster was "more direct" than other campaigns, which tend to take an aesthetic approach rather than using saucy puns. But he says: "I find the whole argument hypocritical. The media that criticised us ran large pictures of the poster. It was an extremely effective campaign."
Like others, Giachino believes the debate can be traced back to a wider backlash against advertising in general. France has one of the strongest anti-advertising movements in Europe, with several groups meeting regularly to demonstrate against what they claim is the pollution of the urban landscape.
Posters in the Paris metro are frequently covered with anti-advertising graffiti.
"These groups, who are a very small minority, are using the idea of sexism in advertising to get the public on their side," Giachino says. "But nobody realises this movement could lead to censorship."
The legendary French ad man Jacques Seguela, the vice-president and chief creative officer of Havas, believes there are wider social forces at work. "We are being touched by a wave of Puritanism that is sweeping towards us from the US," he says. "The west is an ageing society, less rebellious and more family oriented. Following 11 September it has become a paranoid, cocooning society. Everything is about self-protection and restraint."
However, Seguela accepts that some critics have a point. "The French have always been talented at expressing eroticism and sensuality," he says.
"That's why you have this cliche of the great French lover. But now there is a danger that we are moving away from sensuality and into the realm of pornography."
Seguela did not like the Bolero ad, calling it "vulgar". He also cites a slightly older Gucci campaign, made in-house, which showed a young man staring intently at the letter G shaved into a woman's pubic hair. "The important thing to clarify is that most of the offensive ads are not created by advertising agencies, but by fashion designers."
Remi Babinet, the chief executive and creative director of BETC Euro RSCG, picks up this argument. "There is already a law against the public display of pornographic imagery, and self-regulation among agencies functions very well. I would never let anything out of my agency that I considered offensive, and my colleagues have the same sense of responsibility. In fact the industry is liasing with Ameline over this."
Babinet believes that while freedom of expression must be maintained, so must good taste. "Lingerie brands have a right to advertise, and they will inevitably use imagery that revolves around eroticism and the body. But there are subtle ways of doing that. I found the Bolero ad pretty offensive. I felt it steered dangerously close to suggestions of paedophilia."
As a father, Babinet is highly attuned to images that might corrupt children.
"To my mind, it's rather odd that people are picking on advertising posters when magazine kiosks are full of pornographic imagery at the eye level of a nine-year-old."
Babinet also finds it ironic that the debate is raging at the same time as the controversy over government moves to ban Muslim girls from wearing headscarves at school. "Other countries have misinterpreted this action, which is about protecting these young women. It is about ensuring their freedom and equality. The role of women in French society is a complex issue, and advertising is an easy target. But it's not by banning a few posters that you'll make women more liberated."
One lingerie brand that has managed to escape criticism is Aubade, which has been running its sexy-but-classy poster campaigns since the 60s. Ann-Charlotte Pasquier, the brand's marketing director, says: "Our advertising is aesthetic and tasteful. The posters are black and white, and they play on the beauty of the female form. You don't see the model's face, so there is no 'come hither' smile. This allows the female customer to put herself in the place of the model, to fantasise. Above all, it's important to remember that this advertising is aimed at women."
Aubade has not always escaped censure, though. Pasquier notes that in 1968, one of its ads was criticised for showing a woman striking a seductive pose on a bed, while a man looked on. "It just proves that this is an age-old debate," Pasquier says. "But I think we can avoid criticism as long as we place the accent on sensuality, rather than sexuality."