French far-right leader Jean-Marie Le Pen has urged supporters not to vote in Sunday's presidential run-off between Nicolas Sarkozy and Segolene Royal.
Mr Le Pen came fourth in the first round of voting
Mr Le Pen said that neither candidate deserved support from the voters who backed him in first round polling.
The veteran lawmaker came fourth in the 22 April vote, with 10.4% of the vote.
Mr Sarkozy and Ms Royal are now working to secure votes from people who backed him and the third-placed candidate, centrist Francois Bayrou.
Mr Le Pen gave his instructions at his National Front party's May Day parade.
"I call on voters who have shown their confidence in me to cast their vote neither for Madame Royal nor for Mr Sarkozy and to abstain en masse," he said.
Despite Mr Le Pen's instructions, analysts believe that a large majority of his supporters will plump for the centre-right candidate, Mr Sarkozy, who has set out a tough stance on immigration and crime.
Mr Le Pen accuses Mr Sarkozy of poaching his voters, but he told the crowd that this was no reason to vote for the Socialist candidate, Ms Royal.
"It would be illusory and dangerous to vote for the Socialist candidate to get revenge for the hold-up carried out on our programme by Nicolas Sarkozy," he said.
He told his supporters to save their votes for legislative elections in June instead.
Mr Sarkozy and Ms Royal, meanwhile, are also battling for the centre ground and the support of the 18.6% of voters who backed Mr Bayrou.
Mr Sarkozy is thought to be in the lead ahead of a highly-anticipated two-hour televised debate between the two rivals on Wednesday.