Paris prosecutors have begun investigating whether former president Nicolas Sarkozy's winning presidential campaign in 2007 may have received illegal funding from then Libyan leader Muammar Gaddafi's regime.
Prosecutors' office spokeswoman Agnes Thibault-Lecuivre said the probe which opened today centres on claims of corruption, influence trafficking, forgery, abuse of public funds and money laundering.
No one has been named as a suspect.
The probe is based on allegations by Lebanese businessman Ziad Takieddine during questioning by officials in December.
The allegations of Libyan financing emerged in French media last year in the waning days of Mr Sarkozy's losing re-election bid.
Separately last month, a Bordeaux judge filed preliminary charges against Mr Sarkozy over allegations he illegally took donations from France's richest woman in the 2007 election cycle.
Mr Sarkozy has denied any wrongdoing.