Fillon's ratings have gradually recovered after his campaign hit the rocks following nepotism allegations, and on Thursday he redoubled attempts to dissuade his core voters from straying to Macron's camp.

Leading presidential candidates have urged greater counterterrorism measures in a campaign already under a state of emergency.

This two photo combo and provided by the AP on the condition that its source not be revealed, shows Frenchman Clement Baur.

(Christian Hartmann/Pool photo via AP).

Archive reports by French newspaper Le Parisien say that Cheurfi was convicted of attacking a police officer in 2001.

Some ultra-left demonstrators skirmished with police during the Wednesday night protest.

Gaspard Flamant says he fears Le Pen will win the election's first-round vote.

With voters in a rebellious mood and many hesitant to the end about their choices, the identities of the two candidates who will progress to a winner-takes-all May 7 runoff remain anyone's guess. "After Sunday, we will have more information to make a considered risk-return wager to trade and hedge, but high-quality European companies and German bonds look like an attractive bet", Tinker said.

French 10-year bond yields fell briefly to a three-month low earlier on Thursday, though, as polls showed some stability.

Until now, Le Pen had struggled to get the campaign to focus on her party's trademark tough security and immigration stance.

As Fillon's campaign struggled, and with Hollande's Socialist party in shambles, the field opened for the rise of centrist independent candidate Emmanuel Macron.

Diplomats said France needs a leader who will modernise heavily-regulated sectors of the economy and tackle the rigid French labour market, helping to reverse its decline as an economic power relative to Germany over the past two decades. In a statement afterward, Macron insisted on the importance of respecting France's secular traditions but said they shouldn't be used to target Muslims.

(AP Photo/Francois Mori). A supporter holds a placard of French Socialist presidential candidate Benoit Hamon during a last-ditch rally and concert in Paris, Wednesday, April 19, 2017. He pledges a universal income, tax on robots and legal cannabis. "As far back as 1984, this crude, bullying, narcissistic, and bigoted former paratrooper shocked French opinion when his far-right National Front party received almost 11 percent of the vote in elections for the European Parliament". Abysmally unpopular President Francois Hollande declared in December that he would not seek a second term, and it was widely expected that the victor of the conservative Republican party's primary would have a clear path to the presidency.

Some of the candidates later clashed over whether official campaigning, which has just one more day to run, should be brought to a full stop in light of the incident. Authorities announced Tuesday that they had arrested two Islamic radicals suspected of plotting a possible attack around the vote.

"Le Pen's momentum is a slow-moving reaction against the men of Davos - as we have seen with Brexit and Trump - but markets don't want to believe it", Charles Gave told Bloomberg News.

"The other European Union member states would see a Le Pen win as a potentially existential threat to the bloc, especially coming on the heels of the Brexit vote, and would react by digging in their heels", she said.