The surprise winner of the first round of Frances rightwing presidential primary, conservative ex-premier
Fillon, an admirer of Margaret Thatcher who has pledged deep economic reforms, pulled off a stunning upset Sunday, surging from behind to knock his former boss Nicolas Sarkozy out of the race and beat the longtime favourite, Alain Juppe, into distant second.
Fillon and Juppe, also a former prime minister, will go head-to-head in a run-off on Sunday, with the winner expected to meet far-right leader Marine Le Pen in the second round of the presidential election in May.
As Fillon faced immediate attacks from the left as "an ultra-conservative", former centre-right prime minister Jean-Pierre Raffarin also warned that his programme of cuts was "unworkable."
"There is no chance of implementing reforms through brute force," Raffarin, an ally of Juppe, told BFM television on Monday morning.
Polls show Le Pen being beaten at the final hurdle but her rivals have warned that all bets are off in a country where anti-elite sentiment that propelled Donald Trump to the White House is also running high.
Sarkozy's defeat at the hands of his former premier Fillon, a man he once nicknamed "Mr Nobody", marked what appeared to be an ignominious end to the ex-president's forty years in politics.
His hard-right campaign and failure to enact many of his promises when in power from 2007-2012 repelled many voters in his camp.
Conceding defeat for the second time in four years, an unusually humble Sarkozy said it had not been easy for his family to live with a man who "arouses so many strong feelings".
Fillon, a car-racing enthusiast who was premier throughout Sarkozy's 2007-2012 presidency, emerged as a compromise choice between Sarkozy and Juppe, whose reform agenda is seen by many conservatives as too timid.
With nearly all the votes counted Monday, he had won 44.1 percent of the vote in France's first ever rightwing primary, which drew some four million voters, far more than expected.
Juppe, a moderate who campaigned as a unifier, polled 28.6 percent, ahead of Sarkozy with 20.6 percent.
Voters appear to have been won over by Fillon's assured performances in the pre-vote television debates, preferring him to the brashness of 61-year-old Sarkozy or the technocratic, consensus-driven image of 71-year-old Juppe.
The 62-year-old told his ecstatic camp that his programme was one of "hope" and "strong change" after five years of Socialist rule.
In economic terms he is seen as a Thatcherite, who has pledged to cut half a million jobs from France's bloated civil service -- compared to Juppe's 200,000 -- and increase the working week from 35 to 39 hours for both public and private sector workers.
For the rightwing Le Figaro daily, however, his first-round win owed as much to his conservative line on Islam and gay marriage, making him "the incarnation of the tranquil right."
The father of five from Le Mans, a town 200 kilometres (125 miles) south of Paris famous for its 24-hour car rally, has said he opposes gay adoption and would ban the full-body Islamic "burkini" swimsuit.
Fillon was also one of the few candidates to call for closer ties with Russia and voiced support for the regime of Syrian President Bashar al-Assad if not for Assad himself.
General de Gaulle
The infiltration of leftwing voters into the primary could have been a factor in dragging down Sarkozy and boosting both Juppe and Fillon.
Several leftist voters told AFP they took part in the open vote to bar a Sarkozy comeback.
Fillon had campaigned as the only one of the frontrunners with no skeletons in his closet.
jpegMpeg4-1280x720"Who can imagine General de Gaulle being charged with a crime?," he said on the campaign trail, citing the French war hero to take a swipe at Sarkozy and Juppe who have both had legal problems.
jpegMpeg4-1280x720The nomination of the right-wing candidate on November 27 is expected to trigger an announcement from Hollande on whether he intends to bid for re-election despite having the lowest popularity ratings of any post-war president.
Hollande's former economy minister Emmanuel Macron, 38, has announced he will stand as a pro-business independent, adding to his woes.