Former French President
It is believed to be the first time in modern French history that a former leader has been detained by police. Detectives are questioning Sarkozy over allegations that he engaged in "traffic of influence" -- in other words, that he abused his power directly or indirectly.
The conservative ex-president has repeatedly denied any wrongdoing after being targeted by a string of accusations of illegal campaign donations, including money from former Libyan dictator Moammar Kadafi and France's richest woman, L'Oréal heiress Liliane Bettencourt.
This latest move is a blow to Sarkozy's hopes of a political comeback in 2017, when he was expected to seek another term in office after his defeat two years ago by Socialist Francois Hollande.
Sarkozy, 59, arrived early Tuesday morning at police headquarters in Nanterre, on the outskirts of Paris, where he had been summoned for questioning. Officials have not said publicly if he is being interrogated as a witness or as a suspect.
The questioning relates to allegations that he used his influence to glean information on an investigation into irregularities in the funding of his 2007 presidential campaign. Police say information from phone taps on cellphones belonging to Sarkozy and his lawyer, Thierry Herzog, suggests that there was an attempt to be tipped off about the progress of the case. Sarkozy's lawyer and two magistrates, one of whom who was allegedly promised a high-profile job in Monaco if he could pass on information, were also held for police questioning on Monday.
Before his 2012 election defeat, Sarkozy said he would retire from public life if he lost the vote. Since then, however, with his center-right UMP party in leadership disarray, he has appeared increasingly likely to attempt a comeback. During an event at the French parliament last week, Sarkozy said he was "in a period of reflection" about his future.
Investigators can hold Sarkozy for 24 hours but can extend the questioning for another day on a judge's orders. After that, he must be released or formally put under investigation.
In 2011, Sarkozy's center-right predecessor, former President Jacques Chirac, was found guilty of diversion of public funds and breach of trust while he was mayor of Paris and was given a suspended prison sentence. While in power, he had been protected from police questioning by his presidential immunity, and was only brought to court after he left office.