Francois Bayrou failed to provide a significant challenge to the traditional left-right split in French politics as he fell back to 18.5 per cent.
Jean-Marie Le Pen, the far-right candidate, received 11 per cent of the vote, missing out on the second round run-off he reached in 2002.
The projections are based on a sample of the official count.
"It will be worrying times for France if Sarkozy wins the presidency"
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The second round between the two leading candiates will be held on May 6. None of the eight other candidates won more than five per cent of the vote.
About 84 per cent of Frances 44.5 million registered voters turned out to choose a successor to Jacques Chirac, who steps down next month after leading the country for 12 years.
"The French people expressed their desire to let no one else speak for them by putting me first in this first round," Sarkozy told activists at his UMP party headquarters after hearing the projections.
"By putting Mrs Royal in second place, they clearly marked their wish to go to the end of the debate between two ideas of the nation, two projects for society, two value systems, two concepts of politics."
"I want to unite France behind a new French dream ... where no one is left behind," he added.
Sarkozy, the son of a Hungarian immigrant, will probably have to soften his image ahead of the second round after his proposed crackdowns on illegal immigration and crime provoked fears he would divide rather than unite the nation.
Jack Lang, an adviser to Royal, said the result was a "personal victory" for his candidate and urged opposition supporters to unite against Sarkozy.
|Sarkozy: "I want to unite France behind |
a new French dream" [AFP]
"The French people have discovered a coolheaded and serene personality who tomorrow can be a president who will hold the reins of the state. I am calling for a broad coalition against the representative of the outgoing government."
Royal, an army officer's daughter who is hoping to become France's first female president, is also expected to make a move towards the centre to pick up voters who backed the other candidates.
She has presented herself as a nurturing mother figure and has proposed an economic programme that would keep France's generous welfare system intact.
"There are many of us today ... who don't want a France dominated by the law of the strongest and most brutal and blocked in by the power of money where power is concentrated in the hands of always the same few people," she told cheering supporters.Reaching for the centre
"I would tend to think it would be the candidate who could most soften his or her rough edges that will make it through to the presidency," Philippe Chatenay, a journalist from Paris-based weekly Marianne
, told Al Jazeera.
"I think both Ms Royal and Mr Sarkozy must now reach out to the centre, and it will be the one that can do it best who I think will win the Elysee."
The destination of Bayrou and Le Pen's first round votes will have a significant bearing on the second round result.
The centrist candidate refused to say if he would urge his backers to vote for a particular candidate in the second round and a member of his party said Bayrou would "listen" to what the candidates said first.
Le Pen, whose poor showing could spell the end of his political career after five presidential elections, said he would give instructions to his supporters during a speech on May 1.
"I must have made an error in judgement ... I thought the French were unhappy," the National Front leader said as unofficial results placed him fourth.
"The French are very happy and the proof is that they have just re-elected - my goodness, with a very comfortable lead and even a little more - the parties that have been in power and who are responsible for the situation in France."