The most enduring legacy of Franois Mitterrand, France's outgoing president, lies not in politics but in architecture - in the great building projects which he has authorised during 14 years in office. Photographs by EMILE LUIDER. Words by PETER POPHAM
Nowhere else in the Western world could a leader get away with it. American presidents may have their memorial libraries, Lady Thatcher her Downing Street railings. But only in France can the head of state dream of transforming the capital with new buildings, then go ahead and do it.

It has been going on for centuries, since long before the huge reorganization and re-development ordered by Napoleon III in the mid-19th century. Every president has his pet schemes: Georges Pompidou, remembered for the Pompidou Centre, planned to fill the centre of Paris with skyscrapers and freeways, but fortunately died before he could execute the plan. The hubris involved is taken for granted: the president is seen as the agent of history, the man empowered by his people to counterbalance the violence and blindness of change.

The legacy of Franois Mitterrand after 14 years in office is vast. It encompasses such notoriously controversial developments as the glass pyramid of the Louvre and the Grande Arche at La Dfense; the Arab Institute with which the architect Jean Nouvel first made his mark; the huge bulk of the science and technology museum in La Villette and the contrasting forms of the music institute on the same site; and the four L-shaped towers of the new national library on a dockland site in the south-east.

Stylistically, the projets have little or nothing in common: one could not guess that the same sponsor's hand was behind each. What unites them is that they all belong in Mitterrand's grand scheme to make of Paris an ever-greater object of admiration. "Visitors will come to see the Paris of architecture, the Paris of sculpture, the Paris of museums, the Paris of gardens," he wrote in an introduction to the projets, "a city open to imagination, ideas and youth."

Sometimes the president's interventions have been frankly symbolic. It is in the nature of modern cities to sprawl, to fly apart, for more and more homes and businesses to spring up on the periphery, where land is cheap and planning easy. This is not something it is in the power even of French presidents to prevent. But they don't like it: such unchecked, haphazard growth is an insult to the beauty and coherence of the city. Mitterrand vowed to heal the rift. "The city must rediscover its unity," he wrote, "the centre must be put in touch with the periphery and the marginal neighbourhoods."

The result was the Grande Arche de la Defense: the symbolic means by which Paris's periphery was brought back within the president's remit. A dead straight extension of the city's Grand Axe which links the Tuileries and the Arc de Triomphe, culminated in this new triumphal arch, roughly twice the size of the original. Intended as a rival to the Pompidou Centre, the arch is now merely a strangely shaped office building with a bubble-roofed lift taking visitors up into the roof to enjoy the splendid view at 40 francs a time. The park of mirror- glass office buildings over which it presides feels sad and dated despite the huge modern sculptures dotted around it. The periphery remains the periphery: in the dark spaces underneath, kids practise wheelies amidst a pervasive smell of pee. But a steady flow of visitors to the arch wards against the mood of utter desolation which might otherwise have been this area's fate.

Back at the heart of things, Mitterrand's transformation of the Louvre is the achievement for which he is likely to be most fondly remembered. I M Pei's pyramid remains a miraculously simple, elemental solution to the problem of how to infuse an ancient institution with modern spirit without destroying it. With the same bold yet sympathetic approach Pei has quarried an immense new public area underneath the museum, and 40 new galleries have been opened, including those in nearby buildings formerly occupied by the Finance Ministry.

Transparency and lightness are the hallmarks of Pei's work at the Louvre, and these are qualities seen in several of the other projects, too. The Grande Arche is a monstrous hulk, as is the science museum at La Villette. But the Arab Institute disdains structural ostentation and is all about the qualities of light filtered through glass, as is the magical natural history museum in an old building in the Jardin des Plantes.

Not all of Mitterrand's projects have been successful. The Opra Bastille, for example, has been blighted by controversy since its inception, and is widely rated a highly expensive disaster. The presidential prerogative is so great that the citizens quail at the thought of the damage that a truly philistine leader might wreak. But Mitterrand's best buildings demonstrate that, when enough political will, informed by an educated architectural taste, is trained on a city, it can be improved in startling ways.

When Terence Conran pointed out to Margaret Thatcher how Paris was being transformed by the grands projets, she suggested that he design her a new table for the Cabinet. That is the gap, far wider than the Channel, that divides our capital cities; and there is no sign of a tunnel going through.