"Every French president must have his grand project and yesterday Nicolas Sarkozy unveiled his: a vision of a Greater Paris where state-of-the-art transport ends the isolation of deprived suburbs and vast new forests consume its carbon emissions.

Mr Sarkozy, launching an exhibition of the work of 10 architects whom he had invited to imagine the capital of the future, pledged €35bn ($46.4bn, €31.5bn) to improve transport in the greater Paris region and called on local officials to take inspiration from the reflections of some of the world's best-known urban designers.

The flagship of his project, to be financed through public-private partnerships, will be a high-speed 130km elevated metro system linking Paris satellite towns housing technology clusters, universities and industry. The aim is not only to liberate the capital from the confines of its constrictive ring road, which has for 30 years been the dividing line between the traditional city of light and the blight of its neglected suburbs. It is also to stimulate the wider Paris economy by co-ordinating development on a grander scale and take advantage of the faster growth outside the traditional centre.

The president promised to throw open planning and property regulations, to build high-speed rail stations and create 70,000 homes every year, and he expressed a desire to plant a forest of 1m trees near the north-east urban hub of Roissy to reduce carbon emissions.

Mr Sarkozy's vision is far grander than that of any previous president, going well beyond the landmarks left by predecessors such as François Mitterrand and his modern glass pyramid in the courtyard of the Louvre Palace, or Jacques Chirac's homage to ethnic art with the Musée Branly near the Eiffel Tower. His plan, to create an environmentally sustainable green city, where the daily routine is not one of "servitude and alienation" has been billed as the most ambitious urban project since Baron Haussmann's 19th-century reconstruction cleared the narrow streets of the capital in favour of broad boulevards.

But whether the right-of-centre president can actually implement his vision is uncertain. His plans have already sparked controversy in a city and region controlled by Socialists. Even elected officials in his own UMP party have been worried by his suggestion that the creation of a Greater Paris would require a different form of governance.

Yesterday Mr Sarkozy acknowledged that it remained a sensitive issue but also made clear he intended to push forward his plans and fight filibustering attempts. He said his government would propose a bill in October and accelerate bureaucratic processes to allow the project to be completed within 10 years.

Architects and town planners welcomed the initiative but warned that it would have to go well beyond transport to be effective.

Though architects from round the world have proposed radical ideas - from extending Paris right up to the Channel coast to creating a New York-style central park in the heart of the bleak La Courneuve suburb - putting such plans into action could take years.

"If this plan stops with buses it will have accomplished nothing," said Nicolas Michelin, director at the Versailles school of architecture.

"The architects have lots of terrific ideas but tomorrow we will have to come back to earth and ask what can we really do.""