By Dominique Vidalon and Simon Carraud
PARIS (Reuters) - Centrist candidate Emmanuel Macron cemented his status as favourite to win the French presidency on Friday as his conservative rival, Francois Fillon, came under renewed pressure to pull out because of a deepening financial scandal.
For the first time since the line-up of candidates became clear, a poll showed Macron finishing ahead of far-right leader Marine Le Pen in the opening round. It came a day after he promised a blend of fiscal discipline and stimulus to strengthen a feeble economic recovery.
As the former investment banker's campaign gained momentum, Fillon's camp was mired in a crisis of confidence after a string of resignations among his close advisers and backers.
The same poll showed that if Fillon were to step down and be replaced by another former prime minister, Alain Juppe, it would be Juppe winning the first round, with Le Pen eliminated.
A source in Juppe's entourage said the 71-year-old - who lost to Fillon in the November primaries - was "ready to take part in the search for a solution".
Juppe, himself convicted in 2004 for misuse of public funds, has until now ruled out a comeback. "No is no," he tweeted last month.
Veteran centrist Francois Bayrou, who initially backed Juppe before deciding last month to endorse Macron, told France 3 television he would stick with Macron if Juppe replaced Fillon, according to extracts of an interview to be shown on Sunday.
The euro climbed to a two-week high and the spread between French and German 10-year government bond yields fell to its lowest in a month after the Odoxa poll showed Macron pulling ahead of Le Pen, suggesting investors now saw a far-right victory as less likely.
Macron, 39, was economy minister in President Francois Hollande's Socialist government from 2014 to 2016 but has never run for elected office.
He was propelled to the front of the race in part by the scandal engulfing Fillon and on Thursday unveiled a detailed manifesto that included plans to revamp the pension system.
Fillon, who turns 63 on Saturday, this week promised to fight "to the end" despite the scandal over his wife's pay, which he learned this week could see him placed under formal investigation for misuse of public funds later this month.
He has complained of judicial and media bias that amounted to a "political assassination". Several former supporters have since deserted him, saying they cannot support him given his attacks on the judiciary.
On Friday his chief spokesman, Thierry Solere, joined their ranks along with another senior Republican, Dominique Bussereau. Solere did not say why he was quitting.
In a further blow, centre-right party UDI also withdrew its support. The Journal du Dimanche newspaper also published the resignation letter of Fillon's campaign chief Patrick Stefanini, although it was unclear if he had submitted it, amid contradictory reports in the French press.
LE PEN PUSHED INTO SECOND PLACE
Amid intense behind-the-scenes manoeuvring, two senior conservative politicians, Senate President Gerard Larcher and Republicans Secretary-General Bernard Accoyer, held talks on Friday with former President Nicolas Sarkozy to review the situation, a source close to Accoyer told Reuters.
Some lawmakers said Larcher was among conservative politicians who earlier this week urged Fillon to step down in Juppe's favour, but Sarkozy loyalists balked at the idea.
Le Pen also faces legal problems. Her lawyer told Reuters on Friday she had refused to attend a summons by judges over allegations of misuse of European Union funds.
Lawyer Marcel Ceccaldi said Le Pen had told the judges she would not attend before the end of the presidential campaign.
European Union lawmakers on Thursday lifted Le Pen's EU parliamentary immunity in a separate case involving tweeting pictures of Islamic State violence.
The Odoxa poll put Macron on 27 percent in the first round on April 23 with Le Pen behind him on 25.5 percent and Fillon on 19. Le Pen has consistently led first-round polls this year.
In a scenario where Juppe stood in Fillon's place, Odoxa put Juppe in front on 26.5, with Macron on 25 and Le Pen out of the contest on 24 percent.
Daily voter surveys have consistently shown any candidate defeating Le Pen, who promises to pull France out of the euro and hold a referendum on European Union membership, in a May 7 runoff.
A separate poll by Opinionway maintained Le Pen's first-round lead.
Late on Friday, Fillon took to his Twitter feed to urge supporters to attend a rally he will speak at in Paris on Sunday. "Don't let anybody steal this choice from you, I ask you to resist," he said.
(Additional reporting by Michel Rose; Writing by Andrew Callus; editing by Adrian Croft and Richard Lough)