These are some of the ideas coming from Europe's cutting-edge architects who are unveiling their grand vision for a bigger and greener Paris this month.

French President Nicolas Sarkozy last June asked 10 teams of architects and urban planners to imagine a "Grand Paris" that would be among the world's most environmentally-friendly and boldly designed capitals.

The project has been billed as the most ambitious since Baron Haussmann dramatically changed the face of Paris in the mid-19th century when he carved out wide boulevards and the famed Champs Elysees.

For this plan, the chosen visionaries include three Pritzker Prize winners: Richard Rogers of Britain, who gave Paris the Pompidou modern arts centre, Jean Nouvel, who recently won a bid for a landmark Paris skyscraper and Christian de Portzamparc, considered a leading light on urban re-think.

The challenge for the 10 teams was imagining a European metropolis in 30 years time that would be the world's first "post-Kyoto" green urban centre and whose borders would extend beyond the city's current two-million residents.

After nine months of work, the architects have come up with a diagnosis on what ails Paris: its grimy suburbs are not only an eyesore, but an affront to urban living, far removed from shops, workplaces and Paris city centre.

Unlike London which has around eight million people in the city and its suburbs, Paris is home to just two million citizens while at least six million more are scattered across nearby suburbs under separate local governments.

"We need to plant some beauty where there it is now mostly ugliness," said Roland Castro whose team has tackled head-on the "banlieue" that exploded into rioting in November 2005 and have been marred in sporadic violence since.

Castro came up with the Central Park project for La Courneuve, a drab multi-ethnic suburb less than 10 kilometres (six miles) from the centre of Paris that is also home to one of the region's biggest low-income housing estates.

Imagining Greater Paris as a patchwork of places, he also designed a vast national mall, modelled after Washington's open-area park, in Chelles, east of Paris and an opera house in Gennevilliers, on the northwestern fringes.

To better connect the suburbs to Paris proper, Portzamparc proposes a high-speed elevated train that would run along the Paris ring road, seen as the barrier between the city and the suburbs.

He also called for scrapping the city's main train stations to create a single Europe North station.

-- Metropolitan Paris should reach out to the sea --

Metropolitan Paris should not stop at the suburbs but reach out to the sea, according to architect Antoine Grumbach, who proposed building a high-speed train to Le Havre that would be just one hour away from Paris.

Groupe Descartes architects suggested tackling global warming through state-of-the-art forest and water management that would bring average Paris temperatures down by two degrees in 2100.

Others called for improved transport links with tramways, buses and trains and opening up the Seine River to more barges for freight.

From London, the team led by Rogers has taken Sarkozy's call for green living to heart, with plans for rooftop gardens on Paris apartment blocks and turning the main boulevards into greenways for bicycles and pedestrians.

But the number one recommendation from the Rogers team has less to do with green architecture and urban renewal than with French politics.

"We think that Paris has everything in place to be incredibly successful, but one of the key difficulties is fragmentation of government," said Stephen Barrett, from Rogers' team.

"Despite the vast amount of expertise that exists in the city, it's not getting translated into coordinated, coherent action."

That's because the city of Paris is broken into 20 districts, its suburbs lumped into seven departments which in turn are part of a regional government that also encompasses Paris.

The multiple layers of government are derogatively called the "administrative mille-feuille" after the layered puff pastry.

A report by a special task force last week called for doing away with the mille-feuille and creating a single "Grand Paris" from several levels of government, but Sarkozy said he needed more time to consider the prospect.

For months Greater Paris has been a hot political issue, with the Socialist opposition that controls Paris city council and the regional government saying Sarkozy's grand urban plans are a right-wing ploy to undermine the left.

Still the biggest names in architecture agree Paris is in dire need of a re-design.

"When we come out of this economic crisis, wounded but still breathing, the metropolis that will have taken advantage of this time to tackle problems of this magnitude will be the winning metropolis," said urban planner Bernardo Secchi from Venice, one of the 10 participants.

The 10 projects will be presented to the culture ministry this week and unveiled to the public next Tuesday at a special exhibition intended to spark a citizens' debate on the future of the city.

There are no plans to select a winning proposal to be implemented, but the architects hope some of their ideas will become reality or at least inspire a movement for change.

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