The letter is dated 2006 and written in Arabic. It refers to a meeting that allegedly took place between Libyan intelligence officials and Brice Hortefeux, a close aid to Sarkozy. It outlines "an agreement in principle" to provide the Sarkozy campaign with up to 50 million euros in contributions. It is allegedly signed by former Libyan intelligence chief Moussa Koussa.
A controversial Franco-Lebanese businessman named Ziad Takieddine was also named in the report as attending the 2006 meeting. Takieddine denied he was at the meeting but indicated that reports of Libyan funding were credible. "I never witnessed discussions about financing Sarkozy's campaign in Libya. But there is little doubt about its authenticity," he told the French newspaper Liberation. Takieddine is himself under investigation over an arms deal.
Sarkozy has strenuously denied the charges. He has accused the media of bias against him, calling the documents an "obvious fake" and dirty tricks. Moussa Koussa has also denied any connection to the letter.
Sarkozy has also highlighted his leading role in pressing for military action against Qaddafi in 2011. "Do you really think that with what I did to him, Mr Qaddafi would have made me a bank transfer? Why not a signed cheque - it's grotesque" he said to in an interview with France Radio 2.
Analysts note that before his abrupt shift in policy during the Arab Spring, Sarkozy had a positive relationship with the eccentric Libyan leader. In 2007, France welcomed Qadaffi for a state visit where he signed a range of investment and business deals.
The report comes during the final week of France's presidential campaign. Sarkozy is trailing in the polls but had begun to cut some of the gap over the last couple of days. He has stayed on the offensive against his Socialist Challenger, attempting to connect him to former IMF head and leading Socialist Party figure Dominique Strauss-Kahn.