The latest polls in France show that conservative presidential candidate Nicolas Sarkozy and Socialist rival Ségolène Royal are running neck-and-neck. But outside contenders in the vote could upset a clear outcome.

The traditional centrist, pro-European politician François Bayrou and far-right leader Jean-Marie Le Pen have also thrown their hats into the ring.

Voters in France head to the polls on April 22 for a presidential election. A second round of voting is scheduled for May 6 if none of the candidates win an outright majority.

According to the latest survey by LH2 pollsters, Sarkozy is slightly ahead in the first round of voting with 30 percent of votes while Royal would get 27 percent. Bayrou is credited with 17 percent of votes while Le Pen is holding 13 percent. In a runoff, Sarkozy and Royal could both win 50 percent, the survey said.

Front-runners turn on "the third man"

Centrist Bayrou -- dubbed "the third man" in the French press -- has seen a recent surge in his ratings. During a prime-time television performance on Monday night, Bayrou promised he would transcend the left-right divide in France. Analysts said this could explain his growing popularity.

"The two front-runners, how much support do they have -- 25 percent?" Bayrou said on TF1 television. "That's not enough to run the country. That's why we are in the state we are in, because there has not been enough backing for reform."

But both Royal and Sarkozy have criticized his platform.

"I think it's very dangerous," Royal told France Inter radio. "It's trying to stop the French choosing between two models of society, two opposing political visions."

Sarkozy said Bayrou's policies would lead to chaos like that of France's Fourth Republic, when makeshift coalition governments rose and fell repeatedly.

"Democracy is a majority and an opposition and the French have to choose," Sarkozy told RMC radio.

Le Pen focuses on anti-immigrant, anti-Europe platform

Le Pen could prove to be a greater threat to the main candidates than Bayrou, though. The far-right leader is doing better in the race than he was before the 2002 elections. At that time, he stunned the nation by qualifying for the second round of voting against Jacques Chirac. With nearly 17 percent of votes, he beat out Socialist candidate Lionel Jospin.

The 78-year-old launched his election program in Lille over the weekend. In his fifth and probably last bid for the presidency, Le Pen vowed to halt immigration and integration with Europe, which he said was leading France to disaster.

Le Pen told a convention of his National Front Party that he would cut off social benefits to immigrants and "restore France's borders." Amid cheers and chants of "Le Pen, president!" the far-right leader said France was crumbling under poverty, unemployment, the dislocation of factories and "massive immigration."

But French reality has changed over the past five years. In 2002, security and crime topped the list of voters concerns. This had fit well into Le Pen's nationalist anti-immigration platform. Now, Sarkozy has moved into Le Pen's traditional law-and-order territory. Voters' worries have also shifted to jobs and purchasing power, neither of them strong points for Le Pen.