One exhibit is a pants suit ordered from Saint Laurent in 1968 by the American socialite Nan Kempner. "The doorman at a New York restaurant wouldn't let her in because the dress code barred women wearing trousers. So she calmly took off the pants and went in just wearing the jacket as a mini dress."
The exhibition of around 300 models as well as documents and films retraces Saint Laurent's career, spanning 40 years, from his ground-breaking first collection for Christian Dior in 1958, after the founder's untimely death.
Among the earliest works on display are his "trapeze" dresses, which did away with the underpinnings of corsetry, already a decided break with the past.
He went much further in 1960, borrowing from the beatnik youth culture for his Left Bank collection. It was the first time a biker's blouson had ever been seen on a catwalk, albeit in crocodile. The press was scandalised.
"He was stifled by the rituals of a couture house. He was only 21 when he took over at Dior," explains Chenoune.
By the time he opened his own house in 1962, he had already come up with a blueprint for a modern woman's wardrobe built round the trouser suit, the safari jacket and the reefer jacket.
The show gives over a whole room to these three essentials, showing how they evolved over the years.
"His concept was that women look more feminine in a male outfit. At the same time it gives them more power and a new sensuality."
Saint Laurent was always concerned with designing functional clothes for working women, Chenoune notes, pointing to a photo of the actress Charlotte Rampling in a Prince of Wales check trouser suit with her hands thrust in her pockets. "It's liberating. Pockets are a man's handbag."
Although he once said he was "bored" with dressing millionaires, Saint Laurent had his share of celebrity customers and a close inner circle of female friends, from Princess Grace of Monaco and Wallis Simpson to Paloma Picasso, Lauren Bacall, Diana Vreeland and Loulou de la Falaise.
Their clothes get a room to themselves, as does the notorious 1971 "Occupation" collection, with its bitter wartime associations of French women sleeping with Nazis.
The inclusion of furs for summer, as worn by prostitutes in the Bois de Boulogne, was considered particularly vulgar, as vitriolic press reports reproduced on the walls testify. But the show launched the trend for retro, vintage and kitsch, says Chenoune.
Saint Laurent's long-time muse, the actress Catherine Deneuve, has her own wardrobe, with a rail of dresses and rack of shoes, including her costumes from "Belle de Jour", in which she played a bored bourgeoise married woman who turns to part-time work in a brothel.
A room full of grand red carpet gowns and balldresses has an appropriately decadent backdrop from the ball scene in Visconti's classic film "The Leopard", and a whole wall is covered with variations of Saint Laurent's signature tuxedo dresses for women. "At some point, everything he did was also used in a tuxedo dress," Chenoune says.
Another room groups exotic influences from the Ballets Russes to China, Morocco and Africa and his homage to painters, including Mondrian, Van Gogh, Matisse and Picasso.
There is also the complete set of pictures from the photo shoot the designer did in the nude to launch the house's first perfume for men, in which he comes across as a pop icon, a cross between Mick Jagger and Marilyn Monroe, erotic male beauty and the vulnerability of someone who shared his private life with the public, Chenoune says.
"It was also a turning point for glasses. They suddenly became a sexy accessory."
The exhibition is open until August 29.
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