The poll was conducted days after a newspaper report saying his wife was paid taxpayers money for fake work threw his campaign off course. That said, polls show that Le Pen is still a long shot for victory in the second round of voting, with centrist Emmanuel Macron also poised to benefit from Fillon's woes and the Socialists trying to re-build their campaign after the leftist Benoit Hamon won the primaries against the leaders of the party.
Six out of 10 French citizens believe conservative presidential candidate Francois Fillon must drop out following revelations regarding payments he allegedly made to his wife and two of his children using public funds, a survey showed on Friday.
The 62-year-old vowed at an overnight rally in northeastern France to fight what he called a "demolition exercise", telling a crowd of around 1,000: "People are not seeking justice". The lawmakers denounced this "attempted execution" orchestrated by Fillon's opponents and expressed their "total support" to the presidential candidate.
"I feel like someone who is being attacked unjustly on all sides". He held an emergency meeting with party grandees on Wednesday in which he urged them to stick by him for another two weeks - the time he estimated a preliminary investigation would take to run its course.
While polls show Le Pen leading in the first round of voting, they've recently shown Macron close on Fillon's heels for the April 23 first round of voting.
"We need to change tactics, strategy", lawmaker Georges Fenech told RTL radio on Thursday.
Another legislator, Philippe Gosselin, called on former prime minister Alain Juppe, whom Fillon beat in a runoff for the party nomination, to think of stepping in as an alternative.
Should he bow out, other names that politicians have shared with journalists as replacement contenders are Senate President Larcher, publicly proposed by right-winger Christine Boutin on Thursday, and ex-ministers Xavier Bertrand and Francois Baroin.
While much of the rise in bond yields in recent months was caused by a general rebalancing of investor portfolios after the election of Donald Trump as US President, the perception of an increased risk of Le Pen winning the Presidency for the far-right National Front is also weakening investor confidence in French debt.
The uncertainty has increased state borrowing costs, with the spread over German bond yields rising to an nearly two-year high.
However, another poll by Ifop Fiducial offered Fillon some relief by showing him with a slight edge ahead of Macron in the first round, which would allow him to reach the runoff where he would beat Le Pen. The divergence reached the highest level since January 2014.