By Emmanuel Jarry and Dhara Ranasinghe
PARIS/LONDON (Reuters) - Independent centrist candidate Emmanuel Macron appeared to cement his position as favourite for the French presidency on Thursday as the dust settled on a rancorous final televised debate with far-right rival Marine Le Pen.
Three days before the final round of France's most important election in decades, the premium investors demand to hold French bonds over German ones reached its narrowest point in six months, reflecting perceptions that Le Pen, the markets' nightmare scenario as French president, had missed her last chance to unseat Macron.
At stake are two diametrically opposed views of Europe and France's place in the world. Le Pen would close borders and quit the euro currency while Macron wants closer European cooperation and an open economy.
According to a snap poll by Elabe for BFMTV, 63 percent of viewers found Macron the more convincing of the two candidates in Wednesday night's debate, reinforcing his status as favourite to move into the Elysee Palace.
A second poll by Harris Interactive found that 42 percent of people found the 39-year-old Macron more compelling in the debate, during which the candidates traded barbs over the economy, the euro and how to combat terrorism.
Twenty-six percent found Le Pen, 48, more persuasive, while 31 percent chose neither candidate, Harris said.
And on Thursday, a survey of voting intentions by Ifop-Fiducial showed Macron extending his lead over Le Pen to 61-39 percent from 60-40 the previous day.
The first poll on the June parliamentary election, published on Wednesday, showed Macron's year-old En Marche! (Onwards!) movement also set to emerge as the largest party in parliament, suggesting he would be able to push through his programme.
"In France, we still talk about tail risk but that appears to be subsiding after the TV debate," said Commerzbank rates strategist David Schnautz.
Meanwhile, the rancour, accusations and counter-accusations of Wednesday night's two-and-a-half-hour debate between the two candidates continued into Thursday.
The French prosecutor's office launched an investigation into the Macron camp's complaint that fake news was being spread to influence voting.
Macron had earlier denied allegations that he used a foreign tax haven as claimed on social media and referred to by Le Pen during the debate. He accused her of spreading lies.
Separately, Le Pen's campaign issued a statement saying its web site had been regularly attacked by hackers throughout the election race and that it had filed a complaint with the police.
But signs that Macron was more firmly in the driving seat than ever pervaded the day.
Le Pen's niece, Marion Marechal-Le Pen, a National Front lawmaker, said in an interview with L'Opinion magazine and financial website Boursorama that if Le Pen won more than 40 percent of Sunday's vote it would be "an enormous victory" that would position the party "as the only real, credible opposition."
And a small group of protesters threw eggs at Le Pen as she arrived for a campaign event in Brittany on Thursday, shouting "Out with the Fascists!"
Former U.S. President Barack Obama endorsed Macron in a video message released by En Marche! on Thursday, praising him for appealing "to people's hopes and not their fears".
Le Pen's father, Jean-Marie Le Pen, was critical of his daughter's performance, saying most viewers would probably have found the first part of the debate incomprehensible.
"That may have benefited Emmanuel Macron, but it didn't work to the advantage of Marine Le Pen, who perhaps lacked gravitas," the founder of the National Front told RTL radio.
Macron has promised to stimulate economic growth with training programmes and a relaxation of labour laws, while reducing state expenditure.
Campaigning on an anti-EU, anti-globalisation platform, Le Pen has sought to portray Macron, a former investment banker and economy minister, as part of an out-of-touch elite responsible for France's ills, including unemployment of about 10 percent, low growth and a two-year spate of Islamist violence.
On the subject of the alleged fake news, Macron's camp said that, two hours before Wednesday's debate started, an anonymous account posted documents on an Internet forum purporting to prove that Macron had an offshore account, and the information was quickly distributed on Twitter.
Macron's team released a screenshot of what it said was a falsified signature on documents purportedly proving "Macron's secret tax evasion" as well as a trail of tweets spreading the information.
Le Pen told BFM TV on Thursday that she had no proof Macron had an offshore account, but did not want undisclosed funds to come to light when it was too late.
Feike Hacquebord, a researcher with security firm Trend Micro, said last week he had found evidence that Macron's campaign had been targeted by a cyber espionage group linked by some experts to the Russian military intelligence agency GRU.
Russia has denied involvement in attacks on Macron's campaign.
(Additional reporting by Leigh Thomas and Myriam Rivet; Writing by Adrian Croft; Editing by Richard Balmforth and Andrew Callus/Mark Heinrich)