When Alber Elbaz was a young boy, he travelled to school with two bags, one filled with the usual suspects - exercise and text books, pencil case, geometry set and so forth - the second, 'just a little one', carrying crayons and art paper.

'I've always sketched,' he says, 'since I was five years old. And only women. When I was nine, I gave my teacher a notebook full of pictures of all the clothes she wore during that year.'

The young Alber was not quite so proficient where the more obviously masculine side of things was concerned, however.

'Football - are you kidding? When we were divided into teams for any kind of sport, nobody wanted me. I was always left till last and then it was like - you take Alber. My mother told me once that she asked them if it was normal for her son - her macho son - to be drawing all the time instead of playing football.'

'Normal', for what the word is worth, is not, to this day, how one would describe this particular fashion designer.

In place of the social whirl that seems to go hand in hand with the profession, Elbaz is happy to proclaim that he'd rather stay home and watch television, thank you.

'I'm not good at schmoozing with socialites but I love TV, the more stupid the better. For me, it's like meditation. I love Wheel of Fortune especially. You meet an accountant from Omaha, a secretary from Nebraska, a soldier from Connecticut and you realise that the whole world is not just about a red dress and a pair of earrings.'

Neither would one be likely to find Elbaz munching on the lettuce leaf and espresso diet so intrinsic to fashion folklore.

'You know,' he says, 'that bores me. You may live till you're 95 years old and look like you're 11 years old but how miserable would you be?'

That's not to say he's not worried about his weight.

'Do you think I go to the beach in a swimsuit? Never! But then I'm Jewish. I'm a worrier. I worry about everything. I cannot not worry. If you ever see me some time and I'm not worried ⿦ worry.'

Perhaps most significantly, however, in a world that thrives on dictatorial tendencies - despite a loosening of acceptable dress codes, there is still always a certain skirt length, a certain volume, a certain colour that fashion decrees de rigueur - Elbaz is more interested in the idea that his clothes should be determined by those who actually wear them. He may have no time for social niceties but Elbaz regularly travels the world making personal appearances at trunk shows and store openings, meeting his customer and considering her needs. It's small wonder, then, that women love Lanvin - the label he now presides over - in return.

'You know, in the Nineties, designers insisted their clothes should be worn a certain way or styled in a certain direction but I don't think that works any more,' he argues. 'Fashion designers - and design in general - should no longer be about dictating. It's unrealistic and irrelevant to everyday life.'

Over the past five years, Elbaz has transformed France's oldest couture house (founded by Britanny-born Jeanne Lanvin in 1889) from relative obscurity into an internationally respected fashion brand. It remains a small company but a spectacularly successful one none the less. Kate Moss wears Lanvin and so too does Linda Evangelista and just about every fashion editor worth her credentials, but visit a Lanvin store or concession and don't be surprised to see more than just hard-bitten insiders cooing over the softness of the fabric, the intensity of the colour or the flattering nature of the silhouette. Lanvin is, first and foremost, both deceptively simple and unusually easy to wear and the formula is reaping rewards. What's more, sales are not boosted - as is so often the case - with bags, shoes, eyewear and so forth. Any reversal in fortune comes from the women's ready-to-wear line itself. This month, however, sees the launch of Elbaz's first fragrance, Rumeur.

'It's very exciting for me,' says Elbaz. 'The bottle, the smell, the name, the packaging ⿦' Most appealing, he continues, was that Rumeur is not the product of endless market research but of instinct and creativity. 'We didn't think about whether Rumeur sounds good in English, or about whether people would like a scent that is musky but a bit flowery at the same time. We didn't care that the bottle is a little too pared down compared with all the others. I wasn't in the mood for any of that. I wanted something that, 20 years from today, won't be embarrassing.'

Alber Elbaz's family is of Moroccan origin. He was born in Casablanca in 1961 and brought up in Tel Aviv. His father - a hairdresser - died when he was 15 and his mother - a painter - went out to work as a waitress to support her two sons and two daughters. Elbaz has always said that if he hadn't been a designer he would have liked to have been a doctor: 'Not a hospital doctor, a family doctor. To go to the homes of people and penetrate into different stories all the time, and to practise medicine, that is something I'm very sorry I didn't do.'

Following graduation from the Shenkar College of Textile Technology and Fashion, he moved to New York. 'I worked for a company that was doing mother-of-the-bride dresses for $150 or something - and that was expensive. It was like MOB in CDC - you know, crêpe de Chine,' he laughs. 'Coming from the country I came from, I had no choice. I couldn't call the big houses in America so there was no glamour, no wow; you just got there, did the patterns, checked the prices. It was more like doing a jigsaw puzzle than an act of creation. That taught me about fashion as a business.'

After two years, however, things began to look up. In fact, Elbaz was about to be launched sky high. He was introduced to Dawn Mello, the woman best known for installing Tom Ford at Gucci - more of him later - who suggested that this talented young designer might like to work with Geoffrey Beene. 'Now, that had always been my dream,' Elbaz says today.

It did, in retrospect, make perfect sense. Beene was one of the most respected fashion designers of the 20th century, an unparalleled creator of understated luxury and elegance. As the older designer's first assistant and right-hand man, Elbaz was in his element. For this reason, he worked with his mentor for seven years, a lifetime in an ever-more voracious, fast-changing world. 'It was an amazing place to work, the best school,' he says. 'I stayed there because I was happy working a little bit outside the circuit, because he had his vision about fashion, because he had the best style, because he was all about design and because he was a wonderful man.'

By the mid-Nineties, however, it was time to move on. Elbaz relocated to Paris, having been head-hunted by Guy Laroche at which point his work came to the attention of Pierre Berge, the business partner of Yves Saint Laurent. 'M. Berge read an article about my work in Le Figaro and said he would love to be invited to my show so we sent him an invitation and about three hours after the show he called me and asked if I could meet him. So I met him, and M. Saint Laurent was there, and he offered me the job.'

It is now the stuff of fashion legend that Elbaz was chosen personally by the most famous figure in French fashion to design the Yves Saint Laurent Rive Gauche women's ready-to-wear collection when he stepped down in 1998. Elbaz's tenure there lasted only two seasons, however, and this despite critical acclaim. In 1999, the luxury goods conglomerate the Gucci Group bought the label and the aforementioned Mr Ford was unable to resist the challenge of taking over as creative director himself.

'Everything was done in a very professional way,' Elbaz says of the split. 'There was not one article with any of us saying anything bad about each other.' Today, however, he refers to this period as 'his dark room'. Neither has he made any secret of the crisis of confidence that followed, leading him to leave Paris and disappear over night. For a year Alber Elbaz travelled the world and then, having returned and turned down various appointments - 'it doesn't matter what they were' - he finally accepted the position at Lanvin. 'It was all very direct. It was meant to happen. There were no lawyers. We met at two o'clock and at 2.15 I was offered the job. I was so happy because I thought I would never be able to find myself again and all of a sudden I had a tear in my eye.' He pauses for thought. 'I'm such an old lady.'

Although Elbaz is neither elderly nor female, to say he was highly strung would be an understatement. Here he is, for example, describing the genesis of his spring/summer 2007 collection, due to be shown in Paris next month.

'I found myself, on Wednesday, having to sketch the collection and I was very late and had to give everything to the atelier but I couldn't do it because I was too wired. So I took some paper bags and, wearing these ugly gym pants and this ugly shirt, checked into a hotel on the Place de la Concorde. I was feeling alone, miserable and scared that I was not going to be able to fill any of those pages and that the whole weight of the company was on my shoulders. And then, it clicked. I started sketching. It started coming out and, you know what, I've never taken drugs in my life but I know that this must be how you feel when you've taken good drugs, because all of a sudden you have this high that words cannot explain. I put on some music. I put on CNN. I had a piece of paper in front of me and a woman wearing a pair of sunglasses and I stayed there for four days, for four days I didn't leave that room. I slept, I woke up, I ate, I sketched. On Sunday night it was all done. I looked at it and I was sad it was over.'

In the end, for all his considerable skills as both designer and technician, this extraordinary man says that what drives him, above all, is a passion for emotional expression and individuality, and the ability to consider every aspect of his work.

'I am most disturbed by the idea of cloning,' says Elbaz. 'And what I like most in life is to think. Why do you want to use red? What is the significance of red? What is the significance of black? Why do you use it? Is it because we live in dark times? What is the significance of a high waist, of a low waist? I am much more interested in that than in decoration. We're not intellectual but we do think and feel and use our intuition and that is extremely important.'