A magistrate is looking into claims that Mr Juppe was involved in an alleged payroll scam during his time as finance director at Paris City Hall between 1989 and 1993.

Mr Chirac's Gaullist RPR party has run the French capital since 1977. Mr Chirac was the city's mayor until 1995 when he was elected president and Mr Juppe became prime minister.

French newspapers have reported claims that as many as 200 RPR supporters and political friends of Mr Chirac were given fictional jobs financed by local Paris taxpayers.

Several other senior city hall officials have been investigated on charges of demanding kick-backs and illegal commissions for party funds.

BBC Paris Correspondent Stephen Jessel says this latest development brings the investigations into corruption at the city hall a step closer to the president himself.