PARIS — A judge filed preliminary charges Thursday against former president Nicolas Sarkozy in a campaign finance case, formally placing him under investigation over allegations that he illegally took donations from France’s richest woman on way to his 2007 election victory.
The preliminary charges were issued against Sarkozy after he went through hours of questioning in a Bordeaux courthouse, according to the prosecutor’s office.
The former president is accused of ‘‘abuse of someone in an impaired state’’ in the case involving L’Oreal cosmetics fortune heiress Liliane Bettencourt, who is now 90.
Under French law, preliminary charges mean the investigating magistrate has reason to believe wrongdoing was committed, but allows more time to investigate.
The charges may later be dropped or could lead to a trial.
The investigation centers on the finances of Bettencourt, who was once the focus of a long-running family feud over her fortune.
Bettencourt, who was reported to suffer from Alzheimer’s disease, has since been placed under legal protection.
Investigating judge Jean-Michel Gentil was looking into conflicting accounts about how many times Sarkozy — a favorite of the mainstream political right — visited the home of Bettencourt in the run-up to his winning 2007 campaign for president, according to one lawyer.
Earlier in the inquiry, Bettencourt’s former accountant told police she gave $192,000 to the manager of Bettencourt’s fortune that was to be passed on to Sarkozy’s campaign treasurer.
Sarkozy’s lawyer and spokeswoman didn’t return calls, e-mails or text messages seeking comment.