The main candidates in the French presidential election have held their final campaign rallies, and Friday sees the last day of campaigning.
Mr Sarkozy has called for a "rupture" with political traditions
A new opinion poll shows centre-right candidate Nicolas Sarkozy still leading with 29%, ahead of the Socialist Segolene Royal on 25%.
The BVA poll has the centrist candidate Francois Bayrou slipping to 15%.
But at least one-third of voters remain undecided ahead of Sunday's first round. A runoff is expected on 6 May.
All four main candidates headed south for their last rallies.
Mr Sarkozy went to Marseille, while Ms Royal was in Toulouse.
Far-right National Front leader Jean-Marie Le Pen, currently polling about 13%, went to Nice. He came a surprise second in the 2002 election.
Mr Bayrou, leader of the Union for French Democracy (UDF), was in Pau, near his native Pyrenees.
Hard to predict
The BBC's Alasdair Sandford, in Paris, says that with many voters still undecided, the two frontrunners have been turning their fire on Mr Bayrou, each accusing him of belonging to their main rival's camp.
"I knew him for years as a man of the right," said Mr Sarkozy. "For some time now, he's been changing and has become the candidate of the left. The only question is: Did he ask voters if they agree?"
In a French radio interview Ms Royal also accused Mr Sarkozy of trying to win over supporters of Mr Le Pen "at any price", risking "a republican split".
An editorial in the French daily Le Monde urged voters to send Mr Sarkozy and Ms Royal into the second round, saying it was important for two differing "visions of society" to be represented in the runoff.
There are more than one million newly registered voters, the biggest increase in 25 years. Many of them are young people or French living abroad, whose voting intentions are hard to gauge, BBC European affairs correspondent Oana Lungescu reports.
Another novelty is the use of electronic voting machines in some districts, criticised by the Socialists and some other opposition parties as dangerously unreliable. They will be used by 1.5 million voters.
Six out of 10 voters say they trust neither the left nor the right to govern the country, and one in eight is ready to switch allegiance, Oana Lungescu reports.
Ms Royal hopes to become France's first woman president, but left-wing voters are among the most volatile, surveys suggest. She has several rivals on the left who could undermine her support.