Scandal talk clouds French campaign before TV debate

Allegations of scandal and dirty tricks clouded France's presidential election as the race entered the final week with both sides preparing for rival May Day rallies and the sole, crucial television debate.

Conservative President Nicolas Sarkozy said he would sue news website Mediapart for publishing a document it says proves that the government of former Libyan leader Muammar Gaddafi sought to fund his 2007 election campaign.

Sarkozy in turn tried to embarrass his Socialist opponent, Francois Hollande, by turning the spotlight on former IMF chief Dominique Strauss-Kahn, who was favourite for the Socialist nomination until he was arrested on rape allegations last year.

The latest opinion poll showed Hollande's lead over the incumbent has narrowed slightly ahead of next Sunday's decisive runoff ballot.

The Ipsos-Logica poll for France Inter showed the Socialist down one point on 53 percent and Sarkozy up one point on 47. A Reuters survey of polls published since the April 22 first round of voting gives Hollande an average score of 54 percent.

Waging an uphill battle for re-election, Sarkozy dismissed a purported 2006 letter from Libya's former secret service chief, published by Mediapart, that discussed an "agreement in principle" to pay 50 million euros for Sarkozy's campaign.

The case seems unlikely to sway the election at such a late stage in a country where voters are inured to regular sleaze allegations.

"We will file a complaint against Mediapart," Sarkozy told France 2 television. "Do you really think that with what I did to him, Mr Gaddafi would have made me a bank transfer? Why not a signed cheque - it's grotesque."

Sarkozy hosted Gaddafi on an official visit to Paris in 2007 but spearheaded Western military intervention that helped drive the Libyan from power after a 2011 popular uprising.

The president called the document an "obvious fake", saying that the two Libyans who were supposed to have sent the letter and received it had both denied any involvement.

Sarkozy has probably his last chance to turn the tide against Hollande when they face off on television on Wednesday evening for the sole head-to-head debate of the campaign, expected to draw millions of viewers.