French ex-President Nicolas Sarkozy has been detained for questioning over alleged influence peddling.
Mr Sarkozy is being held at Nanterre, near Paris, in an unprecedented step against a former president.
Mr Sarkozy’s lawyer was questioned on Monday on suspicion of seeking inside information about a case against the former leader.
The latest developments are seen as a blow to Mr Sarkozy’s attempts to challenge for the presidency in 2017.
Investigators are trying to find out whether Mr Sarkozy, 59, who was president from 2007 to 2012, had promised a prestigious role in Monaco to a high-ranking judge, Gilbert Azibert, in exchange for information about an investigation into alleged illegal campaign funding.
They are looking into claims that Mr Sarkozy was warned his phone was being bugged as part of the funding probe.
Mr Azibert, one of the most senior judges at the court of appeal, was called in for questioning on Monday. Another judge, Patrick Sassoust, was also questioned, as was Mr Sarkozy’s lawyer Thierry Herzog.
This is thought to be the first time a French former head of state has been held in police custody.
His predecessor, Jacques Chirac, was given a suspended prison sentence in 2011 for embezzlement and breach of trust while he was mayor of Paris.
Investigators will be able to hold Mr Sarkozy for an initial period of 24 hours but can extend custody for another day.
Government spokesman Stephane Le Foll denied any political pressure had been placed on the judicial system to prosecute Mr Sarkozy.
“The justice system is investigating and will follow this through to the end. Nicolas Sarkozy can face justice just like anyone else,” Mr Le Foll said.