French voters were choosing on Sunday between a young, pro-European Union centrist and a eurosceptic, anti-immigration far-rightist for their next president, with official figures and estimates indicating a low turnout.
Opinion polls predicted that the 39-year-old former economy minister Emmanuel Macron would win the five-year presidency, seeing off the National Front's Marine Le Pen after an election campaign full of scandal and upsets.
Voting was not due to end until 8 p.m., but Belgian media published what they said were surveys taken on Sunday by four unnamed pollsters among people who had voted or intended to vote.
The Belgian public broadcaster RTBF said the surveys put Macron's share of the vote at between 62 and 67 percent.
The information could not be verified by Reuters. Pollsters are not allowed to publish election-day surveys in France before voting closes.
But the reported surveys were broadly in line with the last opinion polls on Friday, and pre-election surveys proved accurate for the tight first round between 11 candidates last month.
By midday, both candidates had voted, he in Le Touquet on the north coast, and she in the northern town of Henin-Beaumont.
A victory for Macron, who wants to deregulate the economy and deepen EU integration, would contrast with recent nativist, anti-globalisation voting outcomes such as those that will see Britain quit the EU and made Donald Trump U.S. president.
Should an upset occur and Le Pen win, the very future of the EU could be on the line, given her desire to close borders, dump the euro currency, and tear up trade treaties.
But even in defeat, the 48-year-old's vote is likely to be about twice what her party scored the last time it reached the presidential second round in 2002, demonstrating the scale of voter disaffection with mainstream politics in France.
After a campaign in which favourites dropped out of the race one after the other, this has put her closer to elected power than the far right has been in France since World War Two.
And if polls prove accurate and the country elects its youngest-ever president rather than its first female leader, Macron himself has said himself he expects no honeymoon period.
Close to 60 percent of those who plan to vote for Macron say they will do so to stop Le Pen from being elected to lead the euro zone's second-largest economy, rather than because they fully support the former banker turned politician.
"I don't necessarily agree with either of the candidates," psychotherapist Denise Dulliand, who was voting in Annecy in the mountainous southeast, told Reuters.
"But I wanted to ... be able to say that I came, even if I am really not satisfied with what is happening in our country, and that I would like to see less stupidity, less money and more fraternity."
Figures from the Interior Ministry said 65.30 percent of voters had turned out by 5 p.m., lower than in any of the past four presidential elections at the same stage of the day.
Pollsters' estimates based on these figures put the final turnout at 73-75 percent, down from around 80 percent or more in those past four elections.
Pollsters see likely abstentions - and perhaps blank and spoilt papers - as highest among left-wing voters who feel disenfranchised by Sunday's choice.
It remained unclear what the final turnout would be, and what a high or low showing could mean for the outcome. Polling stations are also open for an hour longer this time.
Markets rose last week in response to Macron's widening lead over his rival after a bitter television debate on Wednesday.
"We increased our equity exposure and added some French stocks after the first round," said Francois Savary, chief investment officer at Geneva-based fund management firm Prime Partners. "The major political risk of a Le Pen victory appears to be disappearing."
But the battle for control of policy will continue into parliamentary elections next month in which the new president will try to secure a majority in parliament. One poll this week suggested that was within Macron's reach.
Whoever wins will open a new chapter in French politics, after the big left- and right-wing movements that have ruled France for decades both suffered humiliating defeats in the election's first round.
The campaign suffered yet another surprise on Friday night, just as the quiet period in which politicians are forbidden from commenting began. Macron's team said a massive hack had dumped emails, documents and campaign-financing information online.
With security a prime concern, more than 50,000 police officers were on duty on Sunday. A series of militant attacks in Paris, Nice and elsewhere in France have killed more than 230 people since 2015.
The courtyard of the Louvre Museum in Paris, where Macron is due to speak after the result, was briefly evacuated on Sunday after a suspect bag was found.