PARIS - Former French President Nicolas Sarkozy is being questioned by judges investigating the finances of his failed 2012 re-election campaign.

Sarkozy, a conservative who is positioning to run again next year, appeared Tuesday before judges investigating the invoice system between his party, then called UMP, and a company named Bygmalion allegedly used to conceal unauthorized overspending.

France had a campaign finance ceiling in 2012 of 22.5 million euros ($25 million). Sarkozy is accused of overspending by 17 million euros ($19 million).

Several people close to Sarkozy, including his former top adviser, already face preliminary charges in the case, one of several linked to the former president, who lost to Francois Hollande in 2012. He has already been fined 364,000 euros ($407,000) for overspending in the case.