French police searched Nicolas Sarkozy's offices and home Tuesday as part of their probe into suspected illegal financing of his successful 2007 presidential election campaign, his lawyer said.

Magistrates are investigating claims that staff for Liliane Bettencourt, heiress to the L'Oreal cosmetics empire and France's richest woman, gave envelopes stuffed with cash to Sarkozy aides to finance the campaign.

The right-winger, who has denied any wrongdoing, lost his presidential immunity from prosecution on June 15 and may now face questioning in a slew of legal probes into corruption and campaign financing violations.

Around 10 financial crimes police officers accompanied investigating magistrate Jean-Michel Gentil in the raid on Sarkozy's home and on offices he has recently rented in Paris, a source close to the enquiry said.

Sarkozy's lawyer Thierry Herzog said the former president, who was defeated in his re-election bid in May by the Socialist Francois Hollande, was currently in Canada with his family.

Le Monde newspaper's website said that investigators had also searched the lawyers' offices where Sarkozy was once an associate.

The ex-president has supplied his diary to judges to disprove claims from witnesses that he attended meetings in the Bettencourt household.

The witnesses, whose testimony was reported in the French press, claimed that Sarkozy held meetings on at least two occasions in the Bettencourt home ahead of his presidential election win in 2007.

Herzog has said that the detailed diary, from the time Sarkozy was interior minister and under strict security restrictions, will prove that claims of him attending meetings at the household were "materially impossible".

Bettencourt is at the center of a series of long-running, overlapping legal inquiries, including one into claims she showered right-wing figures linked with Sarkozy with envelopes stuffed with undeclared campaign donations.

She was placed under legal guardianship in October, ending a long legal battle over her vast fortune, estimated to be worth more than 16 billion euros ($20 billion).

Her family, including estranged daughter Francoise Bettencourt-Meyers, had long accused advisors of taking advantage of the heiress.

Investigating magistrate Gentil has cited two dubious withdrawals of 400,000 euros each from Swiss bank accounts by an intermediary to Bettencourt's close aide Patrice de Maistre.

Gentil in March charged de Maistre with several crimes.

The first withdrawal was made on February 5, 2007, two days before a meeting between de Maistre and Eric Woerth, who was at the time treasurer of Sarkozy's election campaign.

Woerth later became labour minister but resigned in 2010 as the campaign financing probe gathered pace, and in 2011 police carried out searches of his home and offices of Sarkozy's UMP party in connection with the case.

Bettencourt's accountant, Claire Thibout, has testified to having been asked a number of times in 2007 to provide batches of 150,000 euros to Woerth.

The second questionable withdrawal was made on April 26, 2007 -- four days after the first round of the presidential election and over a week ahead of the second round on May 6 that Sarkozy went on to win. (AFP)