Paris (CNN) -- Former French President Nicolas Sarkozy was called in for questioning Tuesday as part of a corruption investigation in connection with an inquiry into alleged abuse of power.
Financial prosecutor Eliane Houlette confirmed that Sarkozy was called in around 8 a.m. local time by police in Nanterre.
Investigators have been looking into Sarkozy's campaign financing, CNN's French affiliate BFMTV reported.
They are trying to establish whether the former President, who led the country from 2007 to 2012, obtained confidential information on legal cases concerning him from top magistrates in exchange for the offer of a prestigious post, the channel said.
Under French law, Sarkozy can be held for questioning for a day, which can be extended once by another 24 hours. The situation is unprecedented for a former president, BFMTV reported.
His lawyer, Thierry Herzog, and two high-ranking magistrates were called in for questioning in the Paris area Monday, according to BFMTV. Their police custody was extended by another 24 hours Tuesday.
Sarkozy left office in May 2012 after he lost in the presidential election to Socialist rival Francois Hollande.
In recent months, speculation has grown that he might be positioning himself for a political comeback at the head of his center-right party, the UMP.
CNN's Jim Bittermann reported from Paris and Laura Smith-Spark wrote in London.