A poll conducted for a newspaper in Paris has shown the leader of France's far-right party could win the first round of next year's presidential election.
The poll, conducted by the Harris Interactive company for the Le Parisien newspaper, with results released on Sunday, puts the National Front leader Marie Le Pen's likely support in next year's vote at 23 per cent, against 21 per cent for the centre-right UMP party led by president Nicolas Sarkozy.
However, the survey itself must be taken with a hint of scepticism, as it was conducted online, a method sometimes seen as less accurate than telephone polling, and it presumed that socialist leader Martine Aubry would be in the race.
But International Monetary Fund director Dominique Strauss-Kahn has signalled he is preparing to declare himself as a candidate for the Socialist Party's nomination - and other polls have shown him favourite if he does.
Despite this, French presidential elections take place over two rounds, so even if Le Pen's score is enough to get into the second round, centrist voters would likely rally behind whichever mainstream candidate joined her there.
This could result in the National Front repeating its result of knocking out the third-placed candidate in 2002.
That prospect has sent shockwaves through the political establishment, and the left is training its fire not on Le Pen, but on Sarkozy - accusing him of stirring dangerous anti-Muslim opinion.
The National Front has always been an anti-immigration party, but under Marie Le Pen, it has attempted to shed its racist image and concentrate the debate on the place of Islam in French society, picking up votes as it has done so.
She also took a bullish view of the poll results, telling French television she was in the race "to win," saying the 2012 elections would bring a "surprise".
"We are facing an ageing political class, which has outdated solutions, hackneyed policies. The National Front represents hope for our people," she told local media.
The French are "fed up of solutions that aren't. They see that over the past three decades their situation has been worsening, that they are being deprived of their country, their culture, and their hopes for the future."
Sarkozy and his UMP have followed suit, taking on the Islam issue in a bid to stop support leaking to the Front and to force the Socialists off topics like unemployment and purchasing power where they have made inroads.
The government has passed a law banning the full-face Islamic veil - worn by only a handful of France's five-to-six million Muslims - from public places. The ban is due to come into effect next month.
Sarkozy last month declared that "multiculturalism is dead" and said he wanted to see a "French Islam and not an Islam in France", while his party has called for a national debate on religious practice in a secular state.
The left, and many Muslim groups, sense a cynical plot. They accuse Sarkozy of stirring up disputes that can only increase tensions in French cities, all in the service of 2012 presidential electoral mathematics.
"It's doubtless a plan by Nicolas Sarkozy to boost the National Front in order to find himself in a head-to-head with them in the second round, and disqualify the left," Socialist parliamentary leader Jean-Marc Ayrault, told AFP news agency.