If Jean Nouvel hadn't had a particular talent for architecture, he would have made a terrific night club bouncer. Unusually tall and imposingly broad, with a polished dome of a head, deep, hooded eyes and a penchant for dressing entirely in black, no one would dare to jump his velvet rope.
As it is, the 64-year-old might not be a household name in Britain, but he is, without doubt, France's best-known architectural export, with an extraordinary list of buildings to his name: from museums and opera houses in France, Denmark and Belgium to apartment blocks and office towers in the United States, Austria, Germany and Japan. He has armfuls of architectural accolades, including the Pritzker Prize, the big American one that architects the world over dream about. On the way are a new Louvre museum in Abu Dhabi and a national museum in Qatar. Indeed, the Abu Dhabi project, due to be completed in 2012, could be his finest hour – an elegant and restrained collection of cubic buildings emerging from water pools, with a perforated dome hovering above.
By the end of this year, the name Jean Nouvel is more likely to be rolling off British tongues too. His Serpentine Pavilion – brilliant red, utterly unavoidable and, in his words, "not an architectural object but an object of pleasure" – has just landed in London's Kensington Gardens, occupying a spot near the Serpentine Gallery until October. Later in the year, the shiny £500m development of shops and offices he has designed at One New Change, near St Paul's Cathedral, will throw open its doors.
Needless to say, the Prince of Wales had a thing or two to say about One New Change. Without seeing the proposed plans for the project. In 2005, he wrote to the developers to object to Nouvel on the basis of his reputation as a modernist. The developer chose not to bother Nouvel with the Prince's objections, and the story only emerged last year.
"I know, I read about it in the magazines,"says Nouvel brightly. "He'd sent a letter saying he'd rather I did something different. [The developer] never said a word to me! Anyway, my building is a homage to [Sir Christopher] Wren. Why would I want to fight with St Paul's?"
Nouvel's story is nothing if not colourful, just like his buildings which can come wrapped in brilliant blue glass (the 2006 Guthrie Theatre in Minneapolis) or hung with 60,000 glass scales lit pink, red, blue and yellow by night (the 2005 Torre Agbar in Barcelona). His architectural status frequently divides opinion, because Nouvel is as inconsistent as he is bold, making buildings that lurch from the dazzlingly beautiful to the uncomfortably wrong. Even the Pritzker jury noted his "varying degrees of success" and his good friend, the star architect Frank Gehry, has noted that the ever curious, shape-shifting Frenchman "tries things, and not everything works".
Nouvel has run a studio in Paris since 1970, but it was his Institut du Monde Arabe in Paris, completed in 1987 as one of François Mitterand's grands projets, that placed him with the major players. Its southern side is a lattice of light-filtering screens that look like traditional Arab architecture and move according to the position of the sun, capturing the imagination of industry professionals and architectural know-nothings alike. In 1994, he added the Cartier Foundation to his Paris projects, a chic, light exercise in glassy modernism, which was hailed a jewel. By contrast, his Musée Branly, also in Paris and completed in 2006, provoked horror.
While his variable output confuses the critics, to Nouvel it's all about doing the right thing for the job in hand. "We need to stop making stereotypical buildings. My specialisation is to consider each place separately, each project, each group of people. I am wedded to the notion of specificity, of context. That will never change!"
In June, a decidedly convivial Nouvel gave an intimate preview of his Serpentine pavilion over lunch in his studio in a quiet courtyard in Paris's 11th arrondisement. He took over the space – an old factory – in 1993, following the near collapse of his company after a trail-blazing Paris project – a 1,400ft tower rising like a slender needle from a tiny base called the Tour sans Fin – bit the dust.
His offices have since spread into every adjoining apartment around the courtyard. Nouvel, currently caring for his health and frame ("I've started swimming, and at some point I might start enjoying it") picks at a plate of vegetables and washes it all down with a good red wine.
Nouvel has the privilege of being the 10th architect to create the Serpentine's summer project. The credential for the job is to be a world-class practitioner with no existing building in the UK. He follows in the glittering footsteps of Zaha Hadid, Oscar Niemeyer and Rem Koolhaas, among others. But this being Nouvel, there is not universal approval. The architecture critic Ellis Woodham, writing in the industry paper Building Design, called the choice "tired and disappointing". But it has to be said, Nouvel's pavilion is anything but.
"It's a special project, between art and architecture," enthused Nouvel as the coffee was poured. "It's about the emotional potential of architecture. As I've said, I like to create buildings that are specific to their context. And here it's Hyde Park – a landscape of freedom where people play."
The Pavilion, with its straight lines and strong geometric shapes, is constructed in metal, translucent polycarbonates and fabrics, all in vibrant red, to contrast with the surrounding green of the park. A sloping, free-standing wall slices into the air for 12 metres on one side. Inside the pavilion, with its spongy red tennis court flooring, are ping-pong tables and swing-ball sets and chess tables. Nouvel himself has a ping-pong table in the extensive but largely empty loft where he lives in the Marais. He used to play chess, too, he says, "but I taught my son, and he started to beat me and I can't bear that. I don't care what it is, I have to win. I can't stand to lose."
Flower beds around the pavilion have been planted with red fruit and flowers, and visitors will find picnic blankets and loungers, swings and seesaws. Red mirrors reflect the surroundings and a single huge photograph, shot 10 years ago in Paris's Luxembourg Gardens by Nouvel's late friend, the philosopher Jean Baudrillard, show the architect's initial inspiration. Last Thursday, as has become customary, the pavilion played host to one of the glitziest parties of the London summer season, with Dinos Chapman, Grace Jones, Dizzee Rascal and others cavorting around the ping-pong tables.
The colour red has punctuated Nouvel's entire oeuvre. The Opera at Lyons, he says, "glows like a heart, glows red". His overwhelming extension to the Reina Sofia in Madrid from 2006 includes a vast and dramatic plane of hovering, polished, red aluminium that almost cancels out the original 18th century building next door.
"Red is symbolic of many things," says Nouvel without elaborating, though elsewhere he told me that "pleasure, eroticism, strong sensations and provocation are the things that interest me".
If red symbolises passion, that suits him too. He's been through several long relationships, with two grown-up sons from the first and a daughter from the second. Then for a few years he stepped out with the gorgeous thirty-something Swedish architect Mia Hagg, though an employee told me he'd recently gone back to No 2 (and also that one of the exes still runs his design studio).
There are even shades of red in the building going up at One New Change, due to open in November. The development, which extends back to Cheapside and faces St Paul's, will be hung with 6,300 glass panels running through grey and red to clear. The result is meant to be shiny, stealthy even, but it currently seems to be a strange shade of grey/brown.
Perhaps Prince Charles has a point; One New Change might not prove to be Nouvel's finest hour. But Nouvel, of course, puts it into context. "It's a difficult project – a whole block which has to enrich the area. But we've added an incredible terrace on the roof with a restaurant, and you feel like you can touch St Paul's. We've added an internal street, just like the pattern of the old City."
On the other side of the cathedral is Paternoster Square, an ungainly mix of Corinthian columns, York stone and cod Italian fascist kitsch that Prince Charles helped to deliver back in 2003. It offers Nouvel a chance to get back at his most regal critic. "[Paternoster Square] is just a caricature of St Paul's. The job is not to create false buildings, at a false scale, with false columns. Pastiche is the worst," insists Nouvel. "A big mistake is better than a false friend."
Serpentine Gallery Pavilion 2010, Kensington Gardens, London W2, to 17 Oct ( serpentinegallery.org). Admission free. Caroline Roux travelled to Paris with Eurostar
Ascent of an architect
1945 Born in Fumel, in France's Périgord region.
1965 Moves to Paris. Wins first prize in a contest to study architecture at the prestigious Ecole des Beaux-Arts.
1971 Begins work for Parent and Virilio in Paris.
1985 Founded Jean Nouvel et Associés.
1987 Awarded the Grand Prix d'Architecture for his work.
1989 Received the Aga Khan Award for Architecture for his acclaimed Arab World Institute in Paris.
1994 Designs Barcelona's Agbar Tower. His architectural firm is made bankrupt.
1998 Constructed the Dentsu building, Tokyo's 11th-tallest skyscraper.
2006 Commissioned to build a new 75-storey tower next to New York's Museum of Modern Art.
2008 Wins the Pritzker Architecture Prize for his "persistence, imagination, exuberance, and, above all, an insatiable urge for creative experimentation".
2010 Unveils design for the Louvre of Abu Dhabi and an extension to the national museum of Qatar.