PARIS — Socialist Francois Hollande and conservative Nicolas Sarkozy go head-to-head in France's presidential runoff, but a third figure looms large in the campaign: the leader of the nation's far-right National Front.
Nearly one in five French voters cast their ballot in the first round for Marine Le Pen, who wants to pull out of the euro currency, reinstate border controls, and crack down on immigrants both legal and illegal.
That means both Hollande and President Sarkozy are likely to reach out to the fringes with populist, protectionist rhetoric just at a time when Europe is seeking steady leadership from France to help lead it out of its catastrophic debt crisis.
Voter frustration with the status quo and with the EU fed a rise of support for extremes at both ends of the political scale, making potential kingmakers out of 11 million voters who supported candidates of the far right and left.
In the biggest surprise of Sunday's first round, voters gave Le Pen a strong third-place showing, handing her far-right National Front almost double the support it got in the last election in 2007 — and the most since her father, firebrand Jean-Marie Le Pen, founded the party.
Wooing the extremes will likely occupy much of the remaining campaign, as how Sarkozy and Hollande divide their support holds the key to who wins the decisive second round May 6. The result has profound consequences not only for the fate of France, but of Europe itself. And as the victor strives to steer a course out of economic turmoil, he may find himself haunted by populist promises made in courting the fringes.
If Hollande wins the runoff, he will become France's first Socialist president since Francois Mitterrand left office in 1995. Polls taken Sunday night continued to show Hollande is likely to best Sarkozy in their head-to-head matchup two weeks from now by around 10 percentage points — in line with the trend of most polls for months.
Both Hollande and Sarkozy resumed campaigning Monday after a two-day pause. Sarkozy was headed to Tours in the Loire valley, while Hollande traveled to Quimper and Lorient in far-western Brittany.
On Monday Sarkozy suggested he'd be tacking at least somewhat to the right for the second round, in a bid to attract disgruntled National Front voters.
"National Front voters must be respected, they've expressed a choice. It's a vote of suffering, a vote of crisis. Why insult them?" Sarkozy said to reporters outside his Paris campaign headquarters.
"I say to them, I've heard you. I'll draw all the consequences," Sarkozy said.
In Brussels, EU officials warned Sarkozy against flirting too much with the extreme right and sacrificing hard-fought European unity, built on the ashes of World War II.
"All the commissioners have appealed to all politicians in Europe to be be careful because there is a threat from radical parties," said EU Commission spokesman Olivier Bailly. Their extreme right values "are fundamentally against the ideals that have led to the construction of Europe."
Hollande blamed Sarkozy for allowing far right ideas to leak into mainstream debate. But he suggested he too would reach out to some of Le Pen's electorate. "Some voters voted for the far right because they're angry (at Sarkozy). They are the voters who I want to hear from," he said in Paris on Monday.
Turnout in France's elections was surprisingly high, at more than 80 percent, despite concern that a campaign focusing on nostalgia for a more protected past would fail to inspire voters.
Le Pen's strong showing handed her a chance to weigh in on French politics with her anti-immigration platform that targets France's millions of Muslims.
"The strength of the populist extreme right shows that there is all over Europe a rise of populism as a result of the economic crisis," said political analyst Dominique Moisi.
Final results from the Interior Ministry showed Hollande won 28.6 percent of the vote and Sarkozy 27.2 percent. Le Pen was in third with 17.9 percent. In fourth place was leftist Jean-Luc Melenchon with 11.1 percent, followed by centrist Francois Bayrou with 9.1 percent and five other candidates with minimal support.
Hollande, a 57-year-old whose victory worried financial markets Monday because of his pledges to boost government spending, vowed to cut France's huge debts, boost growth and unite the French after Sarkozy's divisive first term.
Ten candidates faced off for Sunday's first round of voting, a referendum on Sarkozy at a time when many French voters are worried about high joblessness and weak economic prospects.
Sarkozy is battling to avoid becoming France's first one-term president since Valery Giscard d'Estaing lost to Socialist Francois Mitterrand in 1981. Sarkozy has said he'll pull out of politics if he loses.
The race is now on to sway Le Pen's voters. Le Pen herself told AP last week that she was not going to give instructions to her supporters.
While Sarkozy has borrowed some of Le Pen's anti-immigrant rhetoric and campaign themes of national identity, the far-right leader has repeatedly criticized Sarkozy and says he is a has-been with no chance of returning to office.
Whatever happens to France's leadership will affect the rest of the 27-nation European Union. France was one of six countries that in the 1950s founded the predecessor of the EU, and is the eurozone's second-largest economy after Germany.
Sarkozy and German Chancellor Angela Merkel — a tandem that some call "Merkozy" — have championed a treaty on budget austerity for the 17-nation eurozone. But Hollande wants the treaty to also address economic growth, not just cost-cutting.
On Monday, German government spokesman Georg Streiter said that Merkel "continues to support President Sarkozy." But he added that "the chancellor will work well and outstandingly together with any elected French president."
At a time when voters across Europe have ousted incumbents amid economic woes, an Hollande victory would tilt the continent's political balance to the left.
Hollande, who wants to tax high-income earners at 75 percent, has tapped into a fear of the free market that has always held more sway in France than almost anywhere in the West, and has enjoyed a resurgence in the era of Occupy Wall Street and anti-banker backlash.
• Sarah DiLorenzo, Elaine Ganley, Jonathan Shenfield in Paris, and Masha Macpherson in Tulle contributed to this report.