New Yves dawning: After a decade in the doldrums, Yves Saint Laurent is back on top

It might have been an iconic brand, but Yves Saint Laurent needed a fresh look and some must-have pieces to get back in the black. Luckily, creative director Stefano Pilati and CEO Valérie Hermann are dynamic people...

Extreme simplicity," was how the designer Stefano Pilati described his spring/summer collection for Yves Saint Laurent to the influential American Vogue website, Style.com. "But it has to be feminine and a bit audacious." Any simplicity can be translated, perhaps, as an almost complete lack of superfluous surface embellishment, and a restraint where colour and texture is concerned. In a season characterised by extremes, this seems unprecedented.

Femininity? The belted high waist that Pilati himself brought back into fashion five years ago now, and ahead of its time, was here all present and correct. Underwear peeking out from a coolly unbuttoned silk blouse, masculine jacket or sheer black chiffon shirt – this, of course, is very YSL – was equally suggestive if never vulgar. Heaven forbid.

Then there were the jewel-coloured sequins embroidered across fluid eveningwear, the beautifully judged draping of equally watery silks and quite the most desirable sandals – graphic patent-leather uppers with metal cage heels, which are, incidentally, among the most photographed of the moment.

That leaves audacity. Mr Pilati's work has been nothing if not audacious over the past four seasons in particular. The three-quarter length curved trouser that seemed so surprising when he first sent it out has become ubiquitous both on other people's catwalks and the high street. The pioneering silhouette and exploration of volume that, again, initially seemed like a radical departure from the fitted hour-glass aesthetic the label had long been known for, is now seen as the height of fashionable good taste. As Pilati himself is quick to point out: "You're not going to find shapes like that at Zara."

New for this season, meanwhile, is a voluminous, cropped harem pant – in everything from a dove- grey all-in-one to the iconic tuxedo – and, if in lesser designers' hands, this might appear ungainly, Pilati's command of cut and proportion is such that we could all be forgiven for wanting to wear nothing else. All in all, if any brand has come to embody an entirely modern and quintessentially Parisian elegance and chic, then it is Yves Saint Laurent. And that is as it should be.

2008 was quite a year for the Yves Saint Laurent brand. In May, the great couturier died after a long illness and the world's designers joined his long-time partner, Pierre Bergé, and President Nicolas Sarkozy and his wife to mourn his passing. In the meantime, and under the loving and watchful eye of the aforementioned Pilati and his inspired CEO Valérie Hermann, the fortunes of the house were quietly reversing. It's no secret that since Saint Laurent's own retirement from ready-to-wear in 1998, the company had struggled to make ends meet. Earlier this month, however, it was announced that in the last quarter of the year in question the house moved into profit for the first time in a decade.

"My work has always been accomplished and presented with the consciousness of the financial situation at YSL and the resolve to overcome it," says Pilati of any turnaround. "Of course I am proud of the achievement. It is a milestone but it is, at the same time, just a signal of the beginning."

For her part, Hermann is pragmatic. "The year 2009 proves to be quite interesting," she says, speaking from the YSL HQ in Paris and with more than a trace of irony. "I was very happy we went into profit in 2008 because by the end of that year we were already feeling that the atmosphere was a bit strange. Not only here. I mean, you only have to open a magazine or switch on the TV. Stefano says: 'You know, we have always been in crisis at Yves Saint Laurent.' So we have to be entrepreneurial. We have to see how we can best talk to our customer so they still come into the store. We like challenges at Yves Saint Laurent."

Hermann worked with John Galliano, arriving at his label in 1996, and later at Christian Dior prior to taking up her role at Yves Saint Laurent, arriving just after Pilati's second womenswear show in 2006. The years prior to that were less than stable. In 1999, and following the Gucci Group's acquisition of the ready-to-wear arm of the label, Tom Ford installed himself at its helm – he was also the spectacularly successful creative force behind Gucci itself at the time. ' With his business partner Domenico de Sole at his side, Ford applied a similar strategy to YSL as he had done at Gucci, buying back licences (the practice of lending the brand name to diverse and not always sympathetic products), many of them in Japan, and opening more than 60 stores in the space of four years. ("You know, there were 120 licences," Hermann confirms.)

"It was a huge investment," she says today, "and the right thing to do but it was also bottom-line money." Critically and commercially the adulation that was poured upon Ford for his reinvention of Gucci was rather less forthcoming at Yves Saint Laurent. In November 2003, both he and De Sole acrimoniously split from PPR, the Gucci Group's parent company, and Stefano Pilati was left to hold the reins.

This Italian-born designer worked at Prada before arriving at Yves Saint Laurent in 2000 as assistant to Ford. "Tom Ford taught me a lot," he told me when we first met three years ago. "Through his obsession with sexuality he taught people to be more confident. But we're different, almost opposite, in fact." It is true that Ford's super-charged approach to women's – and indeed men's – dress is quite different from the rather more haute, cool and subtly suggestive look that Pilati has brought to the label. Conversely, the similarities between Pilati and Saint Laurent himself are remarkable.

"But I come from a working-class family in Milan; he always lived in Paris and was surrounded by princesses," Pilati protests. Nonetheless, extreme elegance and clothing that lets a woman express her personality rather than overshadowing it is the over-riding viewpoint here – just as it once was for the master himself. In the meantime, and again just like Saint Laurent before him, there is a certain femininity to the menswear Pilati also now designs, so much so that Unisex, a satellite line that features men's designs tailored to suit women's bodies, is just one of many clever additions to the brand's stable. Then, of course, there are the accessories that have the ability to make or break a brand.

"When I first arrived there were still products missing," says Hermann, and anything other than the clothes themselves was conspicuous in its absence during Ford's tenure. "People said to me when I told them I was moving: 'Fantastic, you're going to Yves Saint Laurent.' I replied: 'OK, what did you buy there recently?' and they couldn't look me in the eye. Yes, it's an iconic brand and yes, I wanted that brand, but it's difficult to be profitable without belts, shoes, bags..."

Enter the Muse bag, a half-moon of butter-soft leather that, since its launch in 2005, has been among the most coveted accessories of the late Noughties. This was followed by the bucket-shaped Downtown and the Muse Two. Then there was the Tribute sandal and, most recently, the YSL Easy – a refreshingly hardware-free bowling bag that is as light as it is roomy and as understated as it is desirable.

As well as Unisex, Hermann and Pilati have come up with Edition 24, a line of more reasonably priced clothing which, safe in the knowledge that not everyone wants to throw out their wardrobe every six months, stays in store for a full year at a time. Then there is Edition Soir, an eveningwear collection that has, in the past three months, been identified as the red- carpet attire of choice by everyone from Carla Bruni to Kate Winslet, who chose to wear it to both the Baftas and Oscars.

It is testimony to her understanding of the creative process that Hermann has kept such potentially money-spinning concerns, all of which Pilati oversees, separate from the main line, allowing the designer entirely free rein on the catwalk. "If you asked Stefano what he thinks of me he'd probably say I was a pain in the neck," she laughs. "I love number-crunching and the market is difficult. Of course, he listens and he's the type of designer who is able to come up with creative solutions to any problems. He also knows, though, that I have a profound respect for him and for creative people in general.

"For a designer, the main line is the most important tool via which to express himself. Every season there may be different products but, in the end, it's always a vision of a strong, elegant, feminine, French woman."

And that, of course, is precisely what the name Yves Saint Laurent stands for.