PARIS: French investigators searched former President Nicolas Sarkozy’s home and office Tuesday as part of a probe into suspected illegal financing of his 2007 presidential campaign by the L’Oreal cosmetics heiress, an official said.

Potential legal troubles have threatened Sarkozy since he lost the presidency to Socialist Francois Hollande in May elections. Sarkozy, who lost his immunity from prosecution June 15, denies wrongdoing.

Judge Jean-Michel Gentil and other investigators from the Paris financial crimes unit conducted Tuesday’s search of Sarkozy’s home and offices, the official said. The official spoke on condition of anonymity because he was not authorized to be publicly named discussing an ongoing investigation.

Messages left with Sarkozy’s staff were not immediately returned.

The probe centers on the finances of France’s richest woman, L’Oreal cosmetics heiress Liliane Bettencourt.

A long-running family feud over her fortune ballooned in 2010 into a multilayered investigation and political affair. Allegations emerged that Bettencourt provided illegal campaign cash to Sarkozy’s party during the 2007 campaign. Sarkozy vigorously denies the claims.

The allegations struck a chord with Sarkozy’s critics, who were frustrated with Sarkozy’s handling of the recession-hit economy and saw him as too cozy with the rich.

An accountant for Bettencourt said in 2010 that she gave 50,000 euros ($63,000) in cash in 2007 to Sarkozy’s party treasurer for the presidential campaign – well beyond the 4,600 euro legal limit on individual donations. A book released last year suggested Sarkozy himself received undeclared campaign money. Sarkozy denies the claims.

The case also stirred up debate over media freedom. Le Monde filed a lawsuit accusing Sarkozy’s office of using counterintelligence services to identify a source leaking information about the investigation.