PARIS (Reuters) - A near win of a third parliament seat by France's anti-immigrant National Front this weekend has sounded a warning to the ruling Socialists over a shift towards the "Eurosceptic" far right by disillusioned voters.
Etienne Bousquet-Cassagne, a 23-year-old with pop star looks who is part of a push by the Front to gain acceptability with fresh young faces, was beaten 53 percent to 47 by a conservative rival in a local by-election runoff on Sunday. His high score has sparked cries of alarm among mainstream politicians.
The Socialists lost the seat in Villeneuve-sur-Lot, near Bordeaux, when a minister quit his post over a Swiss banking scandal, and its candidate to replace him was knocked out in a first-round vote, in part due to anger over the scandal.
Yet it was the latest in a series of by-elections to show support for President Francois Hollande has slid since he won power a year ago, as low-income workers who rallied behind him have grown angry at his failure to rein in rocketing unemployment or end the decay in industry.
The shift in sentiment raises the spectre of street protests as Hollande readies spending cuts and social reforms under the gaze of the European Commission, and it suggests the Socialists will lose ground in municipal and European elections next year.
"The fact the National Front is gaining has been true for a while, but what's new is that it's to the detriment of the Socialist Party," political analyst Dominique Reynie said.
Reynie said the average first-round vote score for the last five by-elections showed support for the Socialists at under 19 percent versus 26 percent in the June 2012 parliamentary ballot.
The National Front has averaged nearly 19 percent, up from 15 percent last June, while the conservative UMP is out in front at 38 percent, up from 35 percent despite party infighting.
Analysts say voters are starting to ignore an old practice whereby mainstream parties would support each other if needed to stop the far-right winning a runoff, as they did in the 2002 presidential second round where left-wingers backed conservative Jacques Chirac against the National Front's Jean-Marie Le Pen.
"What's extraordinary is the slide in support for the Socialist Party. It may be in the process of becoming the third party behind the National Front," Reynie said.
Betraying an air of panic among the Socialists, Industry Minister Arnaud Montebourg lashed out at Brussels on Sunday by saying European Commission President Jose Manuel Barroso and his tough policies were to blame for fuelling far-right sympathies.
Party secretary Jean-Christope Cambadelis said it was time to close ranks. "This is nothing to be proud about," he said.
Sunday's vote followed months of heated street protests against Hollande's legalisation of same-sex marriage, where the sight of young conservatives chanting anti-gay slogans alongside brick-hurling right-wing militants shocked many TV viewers.
The protests betrayed the level of anger over the moribund economy, with many marchers yelling that Hollande should be focused on creating jobs, not marrying gays and lesbians.
Now that the law is passed and gays are tying the knot, the leader of the protests, Frigide Barjot, is struggling to channel her grassroots following into an opposition political movement.
Analysts expect Marine Le Pen's National Front may end up benefitting from the anti-Hollande sentiment she has whipped up, as seemed to be the case in Villeneuve-sur-Lot.
"If we can do 46 percent there, it means we are not far from victory," said an elated National Front Vice President Florian Philippot said, noting the town was hardly a far-right bastion.
"If we held a parliamentary election today, we'd get at least 40 seats," he told Europe 1 radio.
Until now the far right's rise, linked to unemployment and the euro crisis, has been seen as a headache mainly for the UMP, which saw the Front nip at its heels in the 2012 presidential election, taking nearly a fifth of the first-round ballot.
The party now has two members of parliament, the newest being Jean-Marie's 23-year-old granddaughter Marion Marechal Le Pen, the youngest lawmaker in modern France and one who earnestly concedes she has yet to master public speaking.
Even if the far right is far from being able to displace the mainstream right, its success is piling pressure on former president Nicolas Sarkozy's UMP to end months of feuding and agree on a new leader ahead of local elections in March 2014.
As things are, and with Sarkozy's hopes of a comeback dependent on the outcome of a tangle of legal cases, analysts see the National Front well placed to gain there and to overtake the Socialists in 2014 European parliament elections.
"They are going to suck low-income voters away from the Socialists," said Reynie. "Given he has already seen his popularity slump in opinion polls and has lost a handful of lawmakers, Hollande risks ending up with a fragile government."
Reporting By Catherine Bremer; Editing by Michael Roddy