France's former president Nicolas Sarkozy has been detained for questioning in connection with a probe into influence-peddling, a judicial source said Tuesday. Under French law, suspects in criminal cases can be held in custody for up to 48 hours before they must be either charged or released. Investigators are seeking to establish whether Sarkozy, with the help of his lawyer Thierry Herzog, attempted to pervert the course of justice by seeking to obtain inside information from a magistrate about a probe into alleged misdeeds in the financing of his 2007 election campaign. They suspect Sarkozy, 59, was also tipped off that his mobile phone had been tapped by judges looking into allegations that his 2007 election campaign had been financed in part by former Libyan dictator Moammar Gaddafi. Judges last year obtained the unprecedented authorisation to tap the phones of a former president in connection with the Gaddafi investigation, which is ongoing. Investgators eventually discovered that Sarkozy had a secret phone registered under an assumed name. It was conversations with Herzog recorded on that device that triggered the investigation. The legal authorisation to record normally priviledged lawyer-client conversations has provoked criticism from parts of France's legal establishment. Sarkozy's lawyer Herzog and two magistrates were detained Monday for questioning. The charges against France's former leader carry a possible jail term, which would scuttle his hopes of making a political comeback in time for the next presidential campaign in 2017. 'The Bettencourt affair' Sarkozy is alleged to have been helped to victory in 2007 with up to €50 million ($70 million at the time) provided by Gaddafi and envelopes stuffed with cash from France's richest woman, L'Oréal heiress Liliane Bettencourt, when she was too mentally frail to know what she was doing. Sarkozy was cleared last year of taking Bettencourt's money, but his campaign treasurer is one of 10 people still awaiting trial in that case. Leaked excerpts suggest Sarkozy got a friendly judge to try to influence the outcome of confidential legal deliberations related to the Bettencourt case in return for support securing a lucrative post in Monaco. They also imply he had a mole in a senior position who tipped him off about a planned police raid on his offices. Such interference in the judicial process is regarded as "influence-peddling" under French law and carries a maximum prison sentence of 10 years. 'The Tapie affair' Separately, Sarkozy has recently been linked to a scandal over the funding of his campaign for re-election in 2012. The leader of his UMP party resigned last month after it emerged that €10 million ($13.6 million) spent in support of Sarkozy had been fraudulently passed off as party expenses. Sarkozy denies any knowledge or involvement in the falsification of bills for organising campaign rallies and other events. A criminal investigation into that case was opened last week. Authorities are also still investigating longstanding claims that Sarkozy officials rigged a legal settlement to award disgraced tycoon Bernard Tapie €400 million from state coffers in return for his political support in 2007. Sarkozy has been implicated in a number of other scandals which are still being investigated. The most serious of these centres on an allegation that he helped organise kickbacks from a Pakistani arms deal to finance the 1995 presidential campaign of former premier Edouard Balladur. He is also being investigated over allegations that, while president, he used public funds to pay for party political research and handed out contracts for polling to a political crony.