After questioning Sarkozy for 12 hours on Thursday, the three investigating magistrates in the southwestern city of Bordeaux, indicated that they didn't have enough evidence to charge the former president at this time.

"At the end of this hearing, Nicolas Sarkozy was notified of his status as witness," the Bordeaux prosecutor told reporters in a brief statement.

Having been designated as a witness means that the former president is unlikely to be placed under formal investigation unless new evidence agaisnt him comes to light. However, this cannot be completely ruled out.

This was the first time Sarkozy has been questioned about the affair surrounding the 2007 campaign, since he was defeated at the polls by Francois Hollande this past May. Along with losing the presidency, Sarkozy also lost his immunity from prosecution.

Manipulation allegations

Sarkozy is alleged to have received cash-stuffed envelopes from billionaire L'Oreal heiress Liliane Bettencourt, 90, either directly or through intermediaries during his first run for the presidency.

The donations allegedly amounted to 150,000 euros ($193,000), well above the 4,600-euro legal limit on individual campaign contributions.

Prior to Thursday's hearing, French media had speculated that Sarkozy could be charged with taking advantage of Bettencourt's mentally frail state. She was placed under legal guardianship last year after her daughter accused her advisers of manipulating her for personal gain.

French police raided Sarkozy's Paris residence and offices in July as part of the inquiry into financial relations with Bettencourt.

The 57-year-old Sarkozy, who is rumoured to be considering running for president in 2017, has denied any wrongdoing.

pfd/jr (Reuters, dpa, AP)