Panicked passengers fled in terror as a knifeman was arrested at Paris' Gare du Nord station just a day before the French presidential vote.

The drama happened on a day of unrest in the French capital, during which police released tear gas after being pelted with flares and other makeshift weapons in a pre-election riot.

Footage of the station arrest shows armed police surround the man, who was restrained on the ground.

Panicked passengers abandoned their luggage as they fled, and boarding of Eurostar services was briefly suspended this afternoon. Police sources say the arrested man is a 20-year-old from Mali.

Tensions are high across France following Thursday night's ISIS-inspired assassination of police officer Xavier Jugele by fanatic Karim Cheurfi at the Champs Elysee.

Today masked protesters hurled bottles and stones at legions of officers who flooded central Paris following the killing. A 200-strong mob hijacked a peaceful rally organised by left-wing unions and communists.

Voters will go to the polls tomorrow in the first round of the country's presidential election.

Police were seen leading a man away at the Gare du Nord station in Paris this afternoon

The alleged knifeman is seen here lying on the ground as armed police surround him and point their weapons at him

Describing the incident at Gare de Nord, a French police official said that a man carrying a knife walked into the station and was flagged to officers, who arrested him immediately before anyone could be harmed.

French TV network BFMTV reports that the man did not resist arrest, and a police source said he claimed he was carrying the knife because he was afraid for his life. He was not previously known to police.

Another police source added that the arrest caused a 'panic movement' with a number of travellers abandoning their luggage in the middle of the station.

One police source said that some people saw the man, a 20-year-old Malian, 'inside the station, knife in hand' and pointed him out to police, who detained him.

The station was briefly closed before reopening around 4pm. Boarding for Eurostar trains to London was also suspended for a short time, according to an AFP journalist at the scene.

The Gare de Nord is one of the French capital's top transit hubs, serving the city's metro, suburban trains as well as intercity and high-speed trains like the Eurostar from London.

He was told to lie down and followed the orders before he was arrested.

The scene led panic among passengers who tried to flee the scene, a witness said, adding that trains have been delayed.

More police officers involved in the man, who was arrested before anyone was injured by the knifeman

Huge swathes of riot police in Paris had to deploy tear gas after being pelted with flares and other makeshift weapons in a pre-election riot

The planned march, just a day before the country goes to the polls in the first round of the leadership vote, turned ugly with citizens and police clashing, in violent scenes

It comes less than 48 hours after Thursday's murder of police officer Xavier Jugele by ISIS fanatic Karim Cheurfi.

Cheurfi, 39, drove his silver Audi on to the Champs Elysee, the most famous street in the French capital, and 'targeted' officers using a Kalashnikov on Thursday night.

He killed the 37-year-old policeman as he sat in a patrol van at a red light and hit another police officer in the chest, but he survived because he was wearing a bulletproof vest.

'ENOUGH POLICE KILLED AND BURNED' SAY WIVES IN PROTEST More than 100 wives and partners of police protested in Paris today against attacks on police following the assassination of an officer on the Champs Elysee. The Angry Police Wives group marched through the city two days after Xavier Jugelé was shot twice in the head by ISIS sympathizer Karim Cheurfi. At the end of the pro-police demonstration, marchers released black balloons signifying police killed in the line of duty and pink balloons for the families they left behind. The Angry Police wives group took to the streets of Paris to protest this afternoon They carried placards with slogans including 'don't touch my cop' on today's march Some were carrying placards saying 'don't touch my cop', a twist on a well-known French anti-racism slogan. One placard also said "enough police officers killed and burned", referring not only to Mr Jugele's death but also a firebomb attack on a police car carrying four officers by suspected drug dealers in a poor suburb of Paris last October. Two of the officers were seriously wounded in the attack. The protest was held following Thursday's attack which claimed the life of Xavier Jugelé The protest attracted hundreds of partners who work for the French police force Advertisement

Three police officers can be seen in the middle of the shot, attending to an incident on the station floor

Crowds gather following the arrest of a knife-wielding man at Gare du Nord railway station

Karim Cheurfi, 39, drove his silver Audi on to the Champs Elysee, the most famous street in the French capital, and 'targeted' officers using a Kalashnikov on Thursday night

The first poll conducted entirely after Thursday's attack suggested National Front leader Marine Le Pen had gained some ground on frontrunner Emmanuel Macron.

While he was still seen winning the first round with 24.5 percent, his score slipped half a percentage point while Le Pen's rose by one to 23 percent.

Conservative Francois Fillon, a former prime minister, and the far left's Jean-Luc Melenchon were both down half a percentage point on 19 percent in the Odoxa poll for the newspaper Le Point.

The leading candidates have clashed over how to keep citizens safe in the wake of the attack, as residents in overseas territories were pictured casting their votes.

Cheurfi, 39, drove his silver Audi on to the Champs Elysee, the most famous street in the French capital, and 'targeted' officers using a Kalashnikov on Thursday night.

He killed the 37-year-old policeman as he sat in a patrol van at a red light and hit another police officer in the chest, but he survived because he was wearing a bulletproof vest.

MAIN CONTENDERS IN FRENCH PRESIDENTIAL ELECTION Emmanuel Macron A former economy minister of Francois Hollande, the 39-year-old Centrist is the front-runner in the polls. He started a political movement called 'En Marche' that he presents as neither right-wing nor left-wing. The pro-European former investment banker is expected to become France's youngest-ever president because polls suggest if he reaches the run-off on May 7 he would defeat far-right candidate Marine Le Pen. Three surveys show Macron having a slight edge over Le Pen with 23-25 per cent against 22-23 per cent. Macron is married to his former French teacher Brigitte Trogneux, 20 years his senior, and has seven step-grandchildren. Marine Le Pen Le Pen is the candidate of her far-right National Front party. Bolstered by Donald Trump's victory as well as the Brexit result, she is campaigning on an anti-immigration, anti-Islam, nationalist plaform. Following the Champs-Elyees shooting she called for foreign terror suspects to be expelled immediately and said it was a 'ceaseless and merciless war' against France which required 'a presidency which acts and protects us'. She has also pledged to beef up law and order in her manifesto, with 15,000 more police officers, deporting foreign criminals and closing extremist mosques. A study released earlier this week revealed that 51 per cent of French police officers plan to vote for Le Pen in the upcoming polls. That is more than double the number of people who are backing Macron (16.5 per cent). According to the polls, she is currently on 22/23 per cent, but she is likely to be defeated in the second round by Macron. Francois Fillon The longtime No. 2 of former president Nicolas Sarkozy, Francois Fillon was initially installed as the favourite. However his campaign has been dogged by allegations that his Welsh wife and two oldest children improperly received public funds. He said he would step aside before performing a U-turn and he has since received a last-minute boost in the polls and is currently on 20 per cent. Fillon, who penned a pre-election book called 'Beating Islamic Totalitarianism', declared that 'the fight against terrorism must be the absolute priority of the next president'. Vowing to 'destroy Islamic State', he added: 'We are at war, there is no alternative, it's us or them.' Jean-Luc Mélenchon Far-left firebrand Mélenchon the 65-year-old is running for president for the second consecutive time after finishing in fourth place five years ago with 11 per cent of the vote. This year, Melenchon's debating skills, anti-capitalist rhetoric, pugnacity and grasp of social issues have seen him surge in the campaign's closing stages, with 19 per cent in the polls. Melenchon promises to tax the rich and spend heavily, to renegotiate France's role in the 28-nation EU and international trade pacts. He also wants to get rid of what he calls the 'presidential monarchy' by giving more power to parliament, and to stop France's use of nuclear power, the source of nearly 80 per cent of the country's electricity. If Melenchon makes it to the runoff, he is projected to beat both Le Pen and Fillon by comfortable margins although he is seen losing to Macron 41 per cent to 59 per cent. Benoît Hamon Hamon is polling in a distant fifth place ahead of Sunday's first-round election and has little chance of reaching the decisive May 7 run-off - a failure that could crush his Socialist party. He wants to legalise cannabis and tax the wealth generated by robots that take the jobs of humans. Advertisement

And experts agree Thursday's atrocity could tip the scales in Le Pen's favour, ahead of Sunday's election.

Fredrik Erixon, director at the European Centre for International Political Economy, told CNBC: '[It could lead to] a greater performance of Marine Le Pen than otherwise would have been the case.

'It's difficult to see how this attack will not play into the hands of political forces that want this campaign to be focused only on issues around migration and terrorism.'

Vishnu Varathan, senior economist at Mizuho Bank, added: 'The Paris gunman attack may well swing support in her favor; and this may not be picked up by the polls in a timely manner.'

More than half of police officers in France had already said they were voting for Le Pen because of her strong anti-terror stance, according to an IFOP poll.

But some voters, fearful that Le Pen has been strengthened by the instability, said they would shift their votes from fringe candidates to make sure to keep the far-right out of power.

'With an attack such as this one, I think the National Front will get a good result. Therefore I'll change my intention and cast a useful vote - either Melenchon or Macron,' said physics teacher Omar Ilys, 44.

Emmanuel Macron, considered to be the frontrunner for the French presidential election, pictured with his wife Brigitte yesterday

Polling stations have opened today in France's far-flung overseas territories for the country's unpredictable presidential election, as the 11 candidates in the race observed a ban on campaigning.

With voting beginning tomorrow on the French mainland, the government has mobilized more than 50,000 police and gendarmes to protect 70,000 polling stations, with an additional 7,000 soldiers on patrol.

France's 10 percent unemployment and its lackluster economy top voters' concerns as first-round ballots are cast this weekend in the most nail-biting French election in generations.

Opinion polls showed a tight race among the four top contenders vying to get into the May presidential 7 runoff that will decide who becomes France's next head of state.

But the polls also showed that decision was largely in the hands of the one-in-three voters who are still undecided.

Masked protesters hurled bottles and stones at legions of officers who flooded central Paris after a colleague was gunned down in ISIS inspired assassination on the Champs Elysee