French politics has entered uncharted territory after the "big bang" that saw off the presidential candidates of both the traditional left and right parties for the first time.
On May 7, voters will be asked to choose between Emmanuel Macron, a centrist upstart who has never held elected office, and Marine Le Pen, the anti-establishment populist of the far right.
Polls currently show that Macron, 39, will defeat the 48-year-old Le Pen by a wide margin.
But will he be able to govern?
"That's the big question," said Martial Foucault of the CEVIPOF research unit at Paris's Sciences Po university.
"We have no new information" for judging whether Macron's year-old En Marche (On the Move) movement can win an absolute majority in June's parliamentary elections, he said. "It's totally new."
Macron was virtually unknown before his mentor, outgoing Socialist President Francois Hollande, made him economy minister in 2014.
But as Hollande entered the fifth year of a tumultuous presidency, becoming France's most unpopular leader in living memory because of a dismal economic record, Macron struck out on his own.
Styling himself as being "neither of the left or of the right", he has campaigned on a pro-EU, pro-business platform.
But with liabilities such as a slim resume and association with Hollande's failed policies, Macron may owe more than he realises to the fact that he is not Le Pen.
Political scientist Frederic Sawicki, noting "a lack of enthusiasm" for Macron in voter surveys, said: "A lot of people voted to block (Le Pen's) National Front party, but don't share his ideals."
The next two weeks will be "a good test of Macron's ability to represent more than happy globalisation and be the candidate of startups", said Sawicki, of Paris's Sorbonne University.
Traditionally, a newly elected president can count on voters to deliver his (or her) party a majority in parliament.
But either candidate would be starting practically from scratch after what the financial daily Les Echos called Sunday's "big bang".
En Marche -- newly formed -- has no seats in the outgoing parliament, while just two MPs from Le Pen's National Front (FN) sit in the 577-seat body.
En Marche has says it will field candidates in every constituency, half of them drawn from civil society. The party says it has received 15,000 applications.
Macron "wants a solid majority so he can begin to reform the country very quickly," his spokesman Laurence Haim told AFP.
But in addition to new blood, Macron must count on outgoing MPs from both left and right to get behind him.
"He will have to recycle a lot of people from the left," said political analyst Philippe Braud.
So far around 30 Socialist members -- out of 295 in the outgoing parliament -- have rallied to Macron's side while MPs from other parties have hesitated.
Aides say he is already in negotiations to build alliances -- which would result in a "coalition of circumstance", according to Sawicki.
Meanwhile, several commentators said the traditional right will bounce back after Sunday's crushing defeat of the conservative candidate Francois Fillon, who became mired in a fake jobs scandal in January.
"It was not the right that was beaten, it was the personal failure of Francois Fillon," Braud said.
Fillon, once the frontrunner to clinch the presidency, was charged last month with abuse of public funds in a fake jobs scandal involving his wife Penelope.
"The right will turn the page on Francois Fillon very fast and can make big gains," Foucault said, noting that despite the scandals Fillon came in third on Sunday with nearly 20 percent of the vote.
During the campaign, detractors accused Macron of being a closet Socialist channelling Hollande, calling him "Emmanuel Hollande".
The label "may come true", Braud said.
Macron may have to jettison his centrist stance and embrace the centre-left in order to win a majority, Braud said.
The right is already talking about forcing Macron into a cohabitation in which he would have to name a prime minister from Fillon's Republicans party.
"The watchword for the coming weeks is to fight for the majority in parliament and impose a cohabitation on Mr Macron," Republicans MP Daniel Fasquelle said Monday.
The FN, which harbours little hope of Le Pen becoming president, can expect her place in the second round to translate into between 20 and 50 seats, said Bruno Jeanbart of the OpinionWay polling institute.
Editorialist Patrice Chabanet, arguing that voter anger over the status quo was the main factor behind both candidates' victories, described the new political landscape as nothing short of "surreal".
"The upcoming parliamentary vote could bring aftershocks after (Sunday's) earthquake," Chabanet wrote in the Journal de la Haute-Marne newspaper.