Francois Hollande came top with 28.6% and Mr Sarkozy got 27.1% - the first time a sitting president has lost in the first round.
Third-place Marine Le Pen took the largest share of the vote her far-right National Front has ever won, with 18%.
Referring to her voters, Mr Sarkozy said: "I have heard you."
"There was this crisis vote that doubled from one election to another - an answer must be given to this crisis vote," he said.
In a speech to supporters in Tours, Mr Sarkozy also blamed "a media unleashed" for his first round result.
"We were campaigning against caricatures and lies... and I thank you for your support," he said.
Pollsters say Mr Hollande is the clear favourite to win the second round on 6 May, a duel between him and Mr Sarkozy, who leads the centre-right UMP.
If Mr Hollande wins he will become the first Socialist president in France in 17 years.
Intense campaigning has resumed, with Mr Sarkozy travelling to Tours in the Loire Valley, central France, while Mr Hollande went to the western towns of Quimper and Lorient, in Brittany.
Speaking to around 3,000 rain-drenched supporters in Quimper, one of his strongholds, Mr Hollande described himself as the candidate of change.
He said he wanted to speak to all French people, not just the left or right.
"My message? We are a large country and we will recover - we have no need of divisions," he said. » | Monday, April 23, 2012
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