France's established parties are rallying around the man who helped shut them out of the presidential runoff, maverick centrist Emmanuel Macron - an alliance of convenience aimed at keeping far-right Marine Le Pen out of the Elysee Palace. Support for Macron also poured in Monday from the seat of the European Union, as well as German Chancellor Angela Merkel and Jewish and Muslim groups troubled by Le Pen's nationalist vision. European stock markets surged, and France's main index hit its highest level since early 2008, as investors gambled that the rise of populism around the world - and its associated unpredictability in policymaking - may have peaked. For all the paeans to Macron's unifying vision in divided times, it is now up to French voters to decide whether to entrust him with this nuclear-armed nation in the May 7 presidential runoff. Polls consider him the front-runner but that's no guarantee that the French will come together to stop Le Pen the way they stopped her father, Jean-Marie Le Pen, from reaching the presidency in 2002. France's divided political mainstream, rejected by an angry electorate, united Monday to urge voters to back Macron and reject Le Pen's far-right agenda. Politicians on the moderate left and right, including French President Francois Hollande and the losing Socialist and Republican party candidates in Sunday's first-round vote, maneuvered to block Le Pen's path to power. In a solemn address from the Elysee palace, Hollande said he would vote for Macron, his former economy minister, because Le Pen represents "both the danger of the isolation of France and of rupture with the European Union." Hollande said the far-right would "deeply divide France" at a time when the terror threat requires solidarity. "aced with such a risk, it is not possible to remain silent or to take refuge in indifference," he said. Voters narrowed the French presidential field from 11 to two in Sunday's first-round vote, and losers from across the spectrum called on their supporters to choose Macron in round two. Only the defeated far-left candidate, Jean-Luc Melenchon, pointedly refused to back Macron. The contest is widely seen as a litmus test for the populist wave that last year prompted Britain to vote to leave the European Union and U.S. voters to elect Donald Trump president. Le Pen, meanwhile, is hoping to peel away voters historically opposed to her National Front Party, long tainted by racism and anti-Semitism. On Monday, she took a step in that direction, announcing she was temporarily stepping down as party leader, a move that appeared to be aimed at drawing a wider range of potential voters and was in keeping with her efforts in recent years to garner broader support from the left and right. "Tonight, I am no longer the president of the National Front. I am the presidential candidate," she said on French public television news, adding that she wanted to be "above partisan considerations." National Front party officials also joined the chorus, noting that a vote for Le Pen would be a natural move for those fed up with the status quo. "The voters who voted for Mr. Melenchon are angry voters. They can be in agreement with us," Steeve Brios, the mayor of Le Pen's northern bastion of Henin-Beaumont, told The Associated Press, adding that those far-left voters sought choices "outside the system." Also Watch: Choosing from inside the system is no longer an option. Voters rejected the two mainstream parties that have alternated power for decades in favor of Le Pen and the untested Macron, who has never held elected office and who founded his own political movement just last year. Macron's optimistic vision of a tolerant France and a united Europe with open borders is a stark contrast with Le Pen's darker, inward-looking ''French-first'' platform that calls for closed borders, tougher security, less immigration and dropping the shared euro currency to return to the French franc. Le Pen went on the offensive against Macron in her first public comments Monday. "He is a hysterical, radical 'Europeanist.' He is for total open borders. He says there is no such thing as French culture," she said. Le Pen's father, Jean-Marie, made it into a presidential runoff against Jacques Chirac in 2002 and was crushed. Many commentators expect the same fate for his daughter, but she has already drawn far more support than he ever did and she has transformed the party's once-pariah image. Louis Aliot, a National Front vice president and Le Pen's companion, insisted that Le Pen offers an alternative for anyone skeptical of the EU and France's role in it. "I'm not convinced that the French are willing to sign a blank check to Mr. Macron," he said. But Macron's party spokesman, Benjamin Griveaux, scoffed at the idea of Le Pen as an agent of change. "She's been in the political system for 30 years. She inherited her father's party and we will undoubtedly have Le Pens running for the next 20 years, because after we had the father, we have the daughter and we will doubtless have the niece," he said, referring to Marion Marechal-Le Pen. Also Watch: "So she is in a truly bad position to be talking about the elites." Merkel wished Macron "all the best for the next two weeks." And the German chancellor's chief of staff, Peter Altmaier, tweeted that "the result for Emmanuel Macron shows: France AND Europe can win together! The center is stronger than the populists think!" Macron came in first in Sunday's vote, with just over 24 percent while Le Pen had 21.3 percent. Francois Fillon, the scandal-plagued conservative Republican party candidate, came in third with just shy of 20 percent of the vote, just ahead of Melenchon. Socialist candidate Benoit Hamon, whose party holds a majority in the legislature, got just 6 percent of the vote. Turnout was 78 percent, down slightly from 79 percent in the first round of presidential voting in 2012. Protesters angry over the results burned cars, danced around bonfires and dodged riot police overnight at the Place de la Bastille and Republique in Paris. Twenty-nine people were detained at the Bastille, where protesters waved red flags and sang "No Marine and No Macron!"