PARIS (Reuters) - France's far-right National Front (FN) knocked out left-wing rivals and won twice as many votes as the center-right UMP in the first round of a local election in southern France, a sign of growing popularity for the anti-immigrant party.
Results tallied late on Sunday showed FN candidate Laurent Lopez took 40.4 percent of the vote in the canton of Brignoles, near Toulon, in Sunday's vote, versus 20.7 percent for the UMP candidate and 14.6 percent for the Communist.
The National Front's strong showing amounts to a challenge to President Francois Hollande's Socialist Party for mayoral posts in municipal and European elections next year.
"This result is a very serious warning for the left, showing that the National Front is very strong and that we cannot afford to be divided," Socialist Party head Harlem Desir told France Info radio.
"Obviously, I am urging voters to block the National Front in the second round, as I have always done, without any hesitation," he added, an implicit call for voters to back the UMP candidate.
The Socialist Party did not field a candidate, choosing instead to support the Communists. The election's second round, on Oct 13, will be contested by the top two candidates from the first round: the National Front and the UMP.
While Hollande's popularity has sunk, National Front leader Marine Le Pen is winning supporters from both the Socialist Party and the divided center-right UMP as voters rally to her tough positions on crime and illegal Roma encampments.
A TNS-Sofres poll for Le Figaro daily showed her rated as one of the country's most promising politicians, on a par with Francois Fillon, a former UMP prime minister, but well below tough-talking Interior Minister Manuel Valls.
An LH2 poll found that one out of four voters said they would probably or definitely choose the National Front in municipal elections in March. A third of those polled said they do not view the party as "extreme".
In addition to the National Front's 40.4 percent, a far-right independent candidate received 8 percent of the votes in Brignoles, a wealthy Provencal town of some 15,000 inhabitants.
(Reporting by Gerard Bon and Nicholas Vinocur; Editing by Robin Pomeroy)