Hollande needs Leftists to take control of lower house of Parl, currently dominated by conservatives, to carry out his plans to redirect economy.
Sarkozy has repeatedly denied receiving any money from the former Libyan leader Gaddafi.
Opinion polls show the People`s Party, led by Mariano Rajoy, has an unassailable lead over the ruling Socialists.
Support for the government collapsed in the face of the beleaguered economy.
The decision of Social Democratic Party will put pressure on the PM.
Tens of thousands people rallied on Friday in front of the Albanian government building in Tirana, backing calls by the opposition Socialists for a recount of ballots from last year`s elections.
Greece`s Socialists under the leadership of George Papandreou won elections on Sunday after voters expressed their discontent over the conservative government`s handling of the economic crisis and corruption.
Portuguese Prime Minister Jose Socrates` Socialists were re-elected for a second term on Sunday but without the absolute parliamentary majority they currently enjoy, sparking fears of instability.
Day in Pics: 23rd November
Showbiz World - November 23, 2014
Los Angeles Auto Show