THERE are still surprises in store during a French Presidential campaign that has so far been filled with unprecedented twists and turns heading into Sunday’s first-round vote.

With voters in rebellious mood and many hesitant to the end about their choices, the identities of the two candidates who will progress to a winner-takes-all May 7 run-off remain anyone’s guess.

With 11 contenders – from far-left to far-right – for the 47 million registered voters to choose from, the election is a high-stakes test for the European Union and for populist leaders who would tear it down.

Like Donald Trump in the United States, anti-establishment French populists Marine Le Pen and Jean-Luc Melenchon hope for an electoral electro-shock by surfing to power on voter disgust with politics as usual.

Failure by both to qualify for round two would signal a receding of the populist wave that crashed over the EU with the UK’s vote last year to leave.

The months-long French campaign has only seemed to grow weirder and more uncertain as polling day approaches.

A jobs-for-the-family financial scandal that punctured the Mr Clean image and campaign of one-time front-runner Francois Fillon fuelled the raging distrust between voters and their elected representatives.

The siren call of Le Pen’s “France first” nationalist rhetoric, and the late surge by leftist Melenchon leaves Europe’s third-biggest economy at a crossroads, with its future in the EU up for grabs.

The implosion of the ruling Socialist Party, with outgoing president Francois Hollande too unpopular to run again, and the stunning success of his former economy minister Emmanuel Macron with an upstart middle-way grassroots campaign without major party backing, threatens to dismantle post-war France’s traditional left-right political divide.

The threat of Islamist extremism after two years of attacks that have killed more than 230 people, and with police thwarting what the government said was another planned attack this week, means the vote is being held under heightened security, with more than 50,000 police and soldiers mobilised for Sunday.

With the race too close to call, hesitant voters are agonising over whether to follow their hearts or their heads in the first round, meaning either backing their candidate of choice or casting a strategic vote aimed at keeping out candidates they do not want to have to choose between on May 7.

The nightmare scenario for global financial markets is a second-round duel between the equally sharp-tongued Le Pen and Melenchon.Victory for either could, in the wake of the Brexit vote, deliver a possibly knock-out punch to the stated EU ambition of ever-closer union between the peoples of Europe because both want to tear up agreements that bind together the 28 EU states.

Melenchon claims “the Europe of our dreams is dead”, and he proposes “disobeying treaties from the moment we take power” and negotiating new EU rules – followed by a referendum on whether France should leave the bloc it helped found. “We either change the EU or quit it,” his manifesto says.

Like her father in 2002, Front National founder Jean-Marie, Le Pen hopes for an electoral coup by making the run-off. But pollsters suggest that, like him, she would likely lose on May 7 to any of the other top three opponents.

Or, alternatively, voters could step back from the brink of such radical change and opt for the more moderate Fillon, a conservative former prime minister, or Macron, an electorally untested former banker unknown to voters before his two-year stint as Hollande’s economy minister.

Their resilience has been among the election’s many surprises: Fillon because his campaign seemed mortally wounded by revelations that his wife and children benefited from cushy, and allegedly illegal, publicly-funded jobs; and Macron because his start-up electoral campaign caught fire despite hostility from the political establishment.

By quitting Hollande’s government to run as an independent, Macron also sucked away voters from the Socialist Party’s candidate Benoit Hamon. Hamon’s near-irrelevance in the election’s closing stages, with his poll numbers in freefall, presents Socialist electors with the dilemma of whether to “vote utile” – cast a useful vote for a candidate likely to make the second round or waste it on Hamon’s apparently doomed campaign.

Voting stations open at 8am on Sunday, with initial projections expected some 12 hours later, followed by official results.