"When did you last book a weekend in Frankfurt?" Ross McInnes joked after a cross-party group of politicians put the Oxford-educated Franco-Australian chairman of French engine maker Safran in charge of the come-to-Paris campaign.

Bankers in London have sometimes complained that Frankfurt would be boring after life in the British capital.

In Paris' favour, McInnes said the French capital not only offered a deep talent pool of financial and legal experts but an attractive lifestyle unrivalled on the continent.

Paris is vying with Frankfurt, Luxembourg and Dublin to attract banks, insurers, start-ups and investors fleeing Europe's biggest financial centre, since Britons voted to leave the European Union in June.

French authorities have put on a rare united front to promote Paris, with the ruling Socialist government unveiling tax breaks for expats last July while conservative-controlled local authorities have gone on roadshows in New York and launched advertising campaigns.

Stepping up the charm offensive on Thursday, the French government launched a one-stop shop to help firms fleeing London deal with bureaucratic procedures.

McInnes urged foreign investors to look beyond the stereotypes of French red-tape and realise the country has been reforming labour rules and cutting employment costs in recent years.

"Anyone who's worked in France for the last few years knows to go beyond some of the cliches and look at hard facts, hard figures," he said.

"This is a business friendly country," he said, adding that he was living proof as a chairman of a big French company that people do not have to be from the French establishment to make it in France.

Big U.S. banks in particular are looking to shift operations from London to the continent due to the prospect that they will lose their right to serve the full European Union once Britain quits the bloc.

The head of the French Treasury, Odile Renaud-Basso, said that banks were preparing to take relocation decisions in the coming months and that any one financial centre was unlikely to replace London.

"Firms are adopting a strategy of diversification to use the comparative advantages of each centre to their best interest and so activities will be spread around," she told a panel discussion at the French lower house of parliament.

(Additional reporting by Leigh Thomas and Myriam Rivet; Editing by Tom Heneghan)

By Michel Rose