Tear gas has been used against hundreds of protesters on the Place de la Bastille in eastern Paris, with some reportedly beaten with battens.
Hundreds of student protesters, some from anarchist and anti-fascist groups, gathered to protest at far-right candidate Marine Le Pen's second place finish and her anti-immigration policies.
The road to the Bastille Opera is now blocked by police vans and many have taken to Twitter to call the scene "chaos".
More than 50 police officers headed down Boulevard Beaumarchais pushing the protesters towards Bastille
Marine Le Pen is close to becoming President and will face Emmanuel Macron in the final round
A wounded demonstrator lies on the ground following the demonstration
Le Francillien wrote on the social networking site: "So now, what do we do about our democracy and the results? The facists are on their way out."
Paul Guyonnet said: "We are back in Bastille - we don't want either Le Pen or Macron and tonight is the revolution."
Melishkaa said: "People who are protesting in Bastille: I hope you had this much energy when you voted today."
It comes after Emmanuel Macron won the first round meaning he will face Le Pen in the run-off in two weeks' time.
Video thumbnail, Police deployed as riots break out following French election results
Anti-fascists clash with police after the first round of the French Presidential election
French voters went to the polls last night as the first stage of voting to decide the candidate to replace Francois Hollande as leader.
It came at the culmination of a nail-biting election campaign - one of the tightest and least predictable in decades.
Tear gas was used against protesters
Five candidates - Le Pen and Macron plus conservative Francois Fillon, socialist Benoit Hamon and hard-left Jean-Luc Mélenchon - were in close contention for the top two spots in tonight’s poll.
Macron was in first place with 23% of the vote, with Le Pen close behind on 21.6%, according to early results.
Francois Fillon was in third place on 19%, neck-and-neck with socialist candidate Jean-Luc Melanchon.
The two winners from tonight will get on to a second poll, to take place in two weeks time, which will decide the final winner.
The most recent polls had Le Pen on course to get 24% in the first round, with Macron on 23%
Emmanuel Macron
But everything could change in the second round, as voters for the less popular of the eleven original candidates are distributed to the two leaders.
Up to 25% of voters were thought to be undecided up to the day before the vote.
The outcome of the presidential race will have a direct bearing on Britain’s Brexit negotiations.
If Le Pen wins, it could throw the EU project into disarray.
Marine Le Pen, French National Front
The National Front leader has pledged to withdraw France from the Euro and predicted the EU project will eventually die.
Left-winger Melanchon also wants France to leave the bloc.
The outcome will show whether the populist tide that saw Britain vote to leave the EU and Donald Trump elected president of the United States is still rising, or starting to ebb.
But it also provides a choice between radically different recipes for reviving a listless economy that lags its neighbours, and where almost a quarter of under-25s have no job.
A high level of indecision added to the nervousness.
Hanan Fanidi, a 33-year-old financial project manager, was still unsure as she arrived at a polling station in Paris's 18th arrondissement.
"I don't believe in anyone, actually. I haven't arrived at any candidate in particular who could advance things," she said.
"I'm very, very pessimistic."
Despite fears that broad disillusionment with politics could keep voters away, pollsters estimated that the turnout, in fair weather nationwide, would be broadly in line with the last election five years ago, at around 80 percent.
Macron, 39, a centrist ex-banker who set up his party just a year ago, is the opinion polls' favourite to win the first round and then beat far-right National Front leader Marine Le Pen in the two-person runoff on May 7.
(Culled from The Mirror, UK)