Designed by Swiss architects Jacques Herzog and Pierre de Meuron, the tower will stand near the Porte de Versailles congress centre south of the Eiffel and Montparnasse towers -- the two giants of today's Paris skyline.

While a major high-rise complex has sprung up in La Defense business park west of the capital, tower blocks were banned inside Paris proper under a 1977 rule - scrapped by the city authorities in July.

The Socialist mayor of Paris Bertrand Delanoe said the project, financed by property developer Unibail with completion set for 2012, combined high-quality environmental performance with a design of "astonishing beauty".

Construction was due to begin in 18 months on the tower, a sharp pyramid measuring up to 200 metres (660 feet) that will host offices, a conference centre and possibly a hotel, following a public consultation.

Paris city council in July overturned a three-decade ban that limited the height of inner-city buildings to 37 metres (122 feet), launching plans for new towers of up to 200 metres at six emblematic sites just inside the city walls.

Part of wide-ranging regeneration plans, the towers are to mix shops, offices and childcare centres under plans championed by Delanoe despite hostility from green politicians and many Paris residents.

The 37-metre ceiling was brought in in 1977 to call a halt to a string of high-rise projects -- including the Montparnasse tower -- that were quickly seen as failed urbanism experiments.

Delanoe has promised city officials would "not repeat the mistakes of the past".