Only three years away from celebrating its 30th anniversary, the Pompidou Centre is looking outwards. Until now, it has been content with its role as Paris's irresistible powerhouse of modern art. Roughly 150 million people have travelled up its landmark escalator to explore the collections within. The Pompidou's prodigious success is beyond dispute, and its recent extensive renovations have given the centre more space to display the work it owns. But rather than lapsing into Gallic smugness, the Pompidou is aiming to push back its boundaries both at home and abroad.
The centre's president, Bruno Racine, is also acutely conscious that, at any moment, the Pompidou can show only between 1,500 and 2,000 of the nearly 55,000 works in its possession. Given the space-hungry dimensions of so much contemporary art, the problem will escalate swiftly. So a new "antenna" is being erected in Metz, the regional capital of Lorraine, in eastern France. Scheduled for completion in 2007, when the high-speed TGV-Est rail line will also open, the Metz building will provide an extra 6,000 square metres for a rotating display from the Pompidou's ever-expanding collection.
Back at the Paris headquarters, on an early-morning visit before public opening, I witnessed an impressive number of school groups being taken around the current major exhibition: a revelatory survey of Joan Miro's early work. By focusing on the critical period between 1917 and 1934, the show proves just how radical and adventurous the young Miro really was.
Early on, the Barcelona-born artist drew inspiration from the Spanish countryside. Recovering from a serious illness in 1911, he stayed at a farmhouse owned by his father in the remote village of Montroig. Miro loved this primitive retreat so much that, after the Great War, he painted many of his boldest canvases there. In the summer of 1921, he started work on an outstanding image called The Farm. With almost hallucinatory precision, this large and impeccably organised composition celebrates a rural idyll dominated by the spiky, convoluted branches of a eucalyptus tree, sprouting strange black leaves. Ernest Hemingway was so bewitched by The Farm's uncanny Mediterranean stillness that he acquired the painting and announced that he would exchange it for no other picture in the world. But by the time Miro had completed this magisterial work in Paris, he was ready to stage a far more unruly assault on pictorial tradition.
Fired by his irreverent new friends in the emergent surrealist group, Miro let his imagination run riot. Referring to the widespread influence of the cubists, led by his fellow-countryman Pablo Picasso, he announced: "I am going to smash their guitar." Rather than concentrating on still lifes with musical instruments, as so many cubist paintings had done, Miro dived into a dream-world of his own.
Soon, by the mid-1920s, the period when he contributed to the surrealists' first exhibition, his work was hovering on the edge of total abstraction. But Miro's loosely handled paintings were still riddled with anarchic references to a bizarre parade of erotic bathers, amoeba-like creatures, music-hall ushers and, most spectacularly, a moustachioed policeman who seems to be relishing a crazy dance with his horse. Much of Miro's excitability was generated by sexual appetite, with desirable nudes proliferating and an enticing young woman who flaunts herself in a canvas called Landscape on the Banks of the River Love.
Sometimes, amid all this hectic pleasuring, he gives way to a mood of melancholy yearning. In other works, the paint grows increasingly thin and vaporous, and a single eruptive form is often juxtaposed with immense areas of emptiness. Even here, Miro insists on giving his paintings such gregarious titles as A Lot of People. Time and again in this show, extensive passages of cloudy abstraction turn out to be mysteriously attached to graffiti-like images scrawled on the canvas, and called, say, The White Cat or The King's Jester. Then he goes further still, writing messages on the surface of his pictures with the fervour of an infatuated adolescent. In one of his so-called painting-poems, he scribbles the words "Music, Seine, Michel, Bataille and Me" across a work suggestive of a city at dusk, enlivened only by a pink-orange disc and lights spiralling into the dark like fireworks.
For a while, in 1928, Miro becomes obsessed with the interiors of old Dutch paintings, and fills his pictures with elaborate, crisply defined objects, figures and incidents. But they quickly become fantastical, turning into the knobbly form of a giant potato or wriggling, sperm-like creatures in costume. Miro's restless, unpredictable imagination darts everywhere. He suddenly discovers the delights of collage and ready-made materials in the late 1920s. Using a feather, cork and a hatpin on a wooden panel covered in household paint, he produces a graceful Portrait of a Dancer.
But what Miro, in another picture title, calls "the magic of colour" wins out in the end. The exhibition comes to a grand climax with a series of simply named Paintings executed, all of a rush, in 1933. Forms redolent of people, animals, fruit, fish and much else besides are suspended on flat areas of pigment. They gesture, spin, undulate, intertwine and lunge at each other, as if caught up in an inexhaustible dance. Looking at these unfettered images today, we realise how much Miro contributed to the emancipation of modern art with his zestful inventiveness.
"Joan Miro: 1917-34 - la naissance du monde" is at the Pompidou Centre, Paris (00 33 1 44 78 12 33) until 28 June