Paris : Former interior minister Nicolas Sarkozy was the heavy favourite as France's 44.5 million registered voters began casting their polls Sunday to elect their next president.
Polls published late Friday, just before campaigning officially ended, showed the 52-year-old Gaullist with a sizeable and growing lead over his Socialist Party opponent Segolene Royal. The winner is elected for a five-year term.
First estimates will be announced shortly after polls close, at 8 p.m. (local time).
The French are again expected to go to the polls in large numbers, as they did during the first round of the election, on April 22, when 83.77 percent of all registered voters cast their ballots.
In every French election since 1974, the rate of participation was higher in the runoff election than in the first round.
Analysts will be keeping a close eye on the behaviour of the supporters of centrist Francois Bayrou, who came in third on April 22, with 18.57 percent of the vote. Bayrou is set to found a new party next week, which he will call the Democratic Movement.
He did not give his supporters instructions on how to vote, but said that he himself would not vote for Sarkozy.
A heavy defeat for Royal could attract a number of Socialist Party figures to his new party and could make Bayrou a figure to be reckoned with in the legislative elections, which take place on June 10 and 17.