PARIS - Millions of French voters turned out Sunday for the first round of a presidential poll that is expected to see the left oust Nicolas Sarkozy after only one turbulent term in office.
The left has not won a presidential election in a quarter of a century, but with France mired in low growth and rising joblessness, opinion polls predict Socialist challenger Francois Hollande will beat the right-wing incumbent.
Turnout after four hours of voting was strong, at just over 28 per cent the second highest at that stage since 1981, belying fears that a low-key campaign would be capped by mass abstentionism in the vote itself.
Sunday's poll will whittle down the field from 10 to two and Hollande and Sarkozy are expected to face each other in the May 6 run-off to decide who runs France, a nuclear-armed power and Europe's second largest economy.
Hollande says Sarkozy has trapped France in a downward spiral of austerity and job losses, while Sarkozy says his rival is inexperienced and weak-willed and would spark financial panic through reckless spending pledges.
The eurozone debt crisis and France's sluggish growth and high unemployment have hung over the campaign, with Sarkozy struggling to defend his record and Hollande unable to credibly promise spending increases.
"I have never missed a vote, but this time I feel little enthusiasm for the election," said 62-year-old retired high school teacher Isabelle Provost as she emerged into bright Paris sunshine after casting her ballot.
"Economically there is little difference between the two main candidates."
If, as expected, Sarkozy polls second, he will be the only incumbent French president to lose a first round vote in the history of the Fifth Republic, which came into being in 1958.
Hollande voted in his stronghold, the country town of Tulle in the central Correze region, where he is the local member of parliament and heads the regional council and was warmly greeted by officials and voters alike.
"I am attentive, engaged, but first of all respectful," he told reporters. "The day ahead will be a long one, this is an important moment."
Sarkozy and his former supermodel wife Carla Bruni cast their ballots in Paris' plush 16th district, a stronghold of his right-wing UMP party.
Polling began Saturday in France's far-flung overseas territories, and got underway on the European mainland at 8.00am (0600 GMT) on Sunday. It was to continue until 6.00pm in most of the country, and 8.00pm in major cities.
French polling agencies are permitted to take samples directly from ballot boxes, so accurate voting estimates are made public immediately polls close.
More than 44 million voters are registered but pollsters predict around 25 per cent will abstain, a high level by the standards of a French presidential poll and a source of worry to the candidates, especially Hollande.
France is proud of its republican tradition, and the press marked polling day with appeals for a high turnout. "To the voting booths!" declared the newspapers Ouest de France and Voix du Nord.
"At last, we can vote!" declared L'Alsace.
Ten candidates were in the race - Hollande and Sarkozy being trailed by far-right flag-bearer Marine Le Pen, hard-left firebrand Jean-Luc Melenchon, veteran centrist Francois Bayrou and a handful of outsiders.
An average of the last eight polls released ahead of the end of first round campaign at midnight on Friday showed Hollande winning the first round with an average of 28 per cent support, against 26.4 per cent for Sarkozy.
Far-right candidate Marine Le Pen was forecast to poll third with 15.75 per cent, followed by Communist-backed Jean-Luc Melenchon of the Left Front with 13.75 per cent and centrist Francois Bayrou with 10.1 per cent.
Opinion polls and campaigning were banned from midnight on Friday, and will resume on Monday in the build-up to the May 6 run-off, which Hollande is expected to win by around 55 per cent to 45.
Once the first round is out of the way, Sarkozy and Hollande face a two week scramble for the line, including a head-to-head televised debate that could be the incumbent's last chance to change his fortunes.
Privately, Sarkozy's top supporters have begun to admit that if Sarkozy fails to regain the momentum and slip ahead of Hollande on Sunday, he will have too much ground left to make up before the May 6 showdown.