Nicolas Sarkozy is facing a renewed claim that Muammar Gaddafi agreed to donate up to €50m to his last presidential campaign.
The investigative website Mediapart published what it called "compelling new evidence" that the Libyan regime decided to help finance Sarkozy's successful election campaign in 2007. A document that it said was signed by Gaddafi's foreign intelligence chief, Moussa Koussa, stated that the regime had approved a payment of €50m (£40m).
Sarkozy said the document was a fabrication and a disgrace, and accused the French left of using the reports "to create a distraction".
The letter, written in Arabic and dated December 2006, said Tripoli had agreed to "support the electoral campaign" of Sarkozy.
It said an agreement on "the amount and method of payment" had been reachedat a meeting two months earlier involving Brice Hortefeux, a close ally of Sarkozy and then minister for local government.
The, meeting on 6 October 2006,was said to have been attended by Gaddafi's spy chief, Abdullah Senussi, the head of Tripoli's African investment fund, Bashir Saleh, and the Franco-Lebanese arms broker and businessman Ziad Takieddine.
Takieddine's lawyer denied he was present but said the meeting "could certainly have taken place". Saleh, who currently lives in France, issued a statement saying no such document had been sent to him and he had reservations about its authenticity.
Sarkozy is running for re-election and faces a runoff vote against the Socialist François Hollande on 6 May. Hollande's spokesman, Bernard Cazeneuve, said Sarkozy must "explain himself to the French people".
Mediapart, which gained prominence in 2010 when it broke allegations of a political funding scandal involving Sarkozy's UMP party and the L'Oreal heiress Liliane Bettencourt, called for an official investigation.
Sarkozy said on Canal Plus television: "Who led the coalition to topple Gaddafi? It was France. I was perhaps the leader. Do you think that if Gaddafi had anything on me I would have tried to oust him?"
The prime minister, François Fillon, said on French radio it was ridiculous to talk of €50m to finance a campaign that cost €20m and for which accounts were publicly available.
In March, Mediapart published reports of a confidential note suggesting Gaddafi contributed up to €50m to Sarkozy's election fund five years ago. Sarkozy accused Mediapart, staffed by a number of veteran French newspaper and news agency journalists, of being "an office in the service of the left". Its editor, Edwy Plenel, said the website stood by its "serious and reliable" information, based on a 10-month investigation.
Gaddafi's son Saif al-Islam claimed last year that Libya financed Sarkozy's campaign. "Sarkozy must first give back the money he took from Libya to finance his electoral campaign. We funded it and we have all the details and are ready to reveal everything," he told the Euronews network.
Shortly after Sarkozy's election in 2007, Gaddafi was invited to Paris and pitched his Bedouin-style tent in an official French residence near the Elysée. On Wednesday Sarkozy acknowledged that his government had considered co-operation with Libya in civil nuclear energy, having earlier denied it.
