Former French president Nicolas Sarkozy has been questioned by police for a second day over allegations he took millions of euros in illegal campaign funding from late Libyan leader Muammar Gaddafi.

After spending the night at home in Paris, Mr Sarkozy returned to a police station in Nanterre, north-west of the French capital, to be questioned by anti-corruption police officers, a person with direct knowledge of the case told the Associated Press.

An investigation has been under way since 2013 into the case, involving funding for Mr Sarkozy’s winning 2007 presidential campaign.

Investigators are examining claims that Gaddafi’s regime secretly gave Mr Sarkozy 50 million euros overall for the campaign.

The sum would be more than double the legal campaign funding limit at the time – 21 million euros. In addition, the alleged payments would violate French rules against foreign financing and requiring that the source of campaign funds be declared.

Mr Sarkozy, 63, who was president from 2007 to 2012, has repeatedly denied any wrongdoing. He could be handed preliminary charges when his hearing is done.

No details from Mr Sarkozy’s first day of questioning have emerged. His lawyer, Thierry Herzog, did not respond to requests for comments.

Mr Sarkozy’s former top aide, ex-minister Brice Hortefeux, was also questioned on Tuesday but not detained. He said on Twitter after his hearing that the details he gave to investigators “should help put an end to a series of mistakes and lies”.