Former French President and conservative party UMP leader Nicolas Sarkozy gives a speech following the final round of French local elections, in Paris, France, Sunday, March 29, 2015. French voters are choosing members of local councils in run off elections Sunday seen as a test for the far right National Front, which is expanding its presence in French politics. The mainstream conservative UMP party came out ahead in the first round, ahead of the National Front and the governing Socialists. (AP Photo/Thibault Camus)
PARIS — Former French President Nicolas Sarkozy has been designated a key witness in a judicial investigation of financing of his failed 2012 re-election bid.
Wednesday's move by an investigating judge amounts to a new legal headache for Sarkozy as he seeks to reconstruct his political career and possibly mount a re-election bid in 2017.
It comes three days after his conservative UMP party handily won local elections, which has been seen by many observers as a positive political sign for him.
The case centers on hundreds of thousands of euros in fines paid by the UMP after France's constitutional court ruled two years ago that Sarkozy's 2012 re-election campaign exceeded legal funding limits. Investigators believe he — not the party — should have paid the fine.
The constitutional court ruling also stripped the party of state reimbursements and left it with an 11-million-euro ($11.8 million) bill.
After Sarkozy was questioned by the investigating judge on Wednesday, the Paris prosecutor's office said he has been named an "assisting witness." Under French law, that means he has not been directly accused of any wrongdoing, but leaves open the possibility that he could be later.
Paris prosecutors launched an investigation in the case in October for suspected breach of trust.
Sarkozy has other legal troubles. Last year, he was handed preliminary charges in an investigation of allegations that he received 50 million euros ($54.5 million) in illegal campaign funds from former Libyan leader Moammar Gadhafi. Sarkozy has denied any wrongdoing.
On Sunday, the UMP chalked up wins across France in local elections that saw President Francois Hollande's Socialists lose nearly half of the councils it controlled.