French President Nicolas Sarkozy faces an uphill struggle in the second round of the presidential election, after coming second in Sunday's first vote. He won only 27.1% of the vote, while his socialist rival Francois Hollande took 28.6%, the first time a sitting president has lost in first round. Third-place Marine Le Pen took the largest share of the vote her far-right National Front has ever won with 18.1%.
The two men will face each other in a second round of voting on 6 May.
Analysts suggest Mr Sarkozy will now need to appeal to the far-right voters who backed Ms Le Pen if he is to hold on to the presidency, but Mr Hollande remains the front runner.
Around one in five people voted for the National Front candidate, including many young and working class voters, putting her ahead of seven other candidates.
The poll has been dominated by economic issues, with voters concerned with sluggish growth and rising unemployment.
After the results began to come in, Mr Hollande said he was best placed to become the next president of the republic and that Mr Sarkozy had been punished by voters.
The choice is simple: either continue policies that have failed with a divisive incumbent candidate or raise France up again with a new, unifying president, Mr Hollande said.
It is the first time a French president running for re-election has failed to win the first round since the start of the Fifth Republic in 1958.
Mr Sarkozy - who has been in power since 2007 - said he understood the anguish felt by the French in a fast-moving world. He called for three debates during the two weeks to the second round - centring on the economy, social issues, and international relations.
Turnout on Sunday was high, at more than 80%.
Ms Le Pen, who leads the anti-immigration National Front, achieved more than the breakthrough score polled in 2002 by her father and predecessor, Jean-Marie Le Pen, who got through to the second round with more than 16%.
After the vote, Ms Le Pen told jubilant supporters that the result was only the start and that the party was now the only opposition to the left.
Leftist candidate Jean-Luc Melenchon, who was backed by the Communist Party, came fourth with almost 12%. He urged his supporters unconditionally to rally behind Mr Hollande in the run-off.
Centrist Francois Bayrou who was hoping to repeat his high 2007 score of 18% only garnered about 9%.
Polls suggest Mr Hollande will comfortably win the second round.