LA TRINITE-SUR-MER, France (Reuters) - Florent de Kersauson, a French far-right parliamentary candidate, was leafleting in Brittany when his deputy called to say reporters had found an old, antisemitic tweet by a fellow National Rally (RN) contender in a neighbouring constituency.

De Kersauson, one of 27 candidates hoping to win the RN's first seat in the historically left-leaning region, was furious, mindful of the damage Joseph Martin's comments could cause his party's pursuit of power.

"What was this idiot doing saying bullshit like that?" de Kersauson said of Martin's tweet.

For decades, the National Rally's reputation for antisemitism, Islamophobia and racism made it a non-starter for millions of French voters, but Marine Le Pen's efforts to detoxify the party her father established in the 1970s under the National Front banner has broadened its appeal.

Opinion polls show the RN winning the two-round parliamentary election on June 30 and July 7, but without an absolute majority. That would likely force centrist, europhile President Emmanuel Macron to share power with an anti-immigrant, eurosceptic government.

Voter anger at the cost of living and towards Macron has made the prospect of the RN winning seats for the first time in Brittany appear possible. The RN's rise in Morbihan, a Breton district of Neolithic stone circles popular with tourists, mirrors a national trajectory.

In the 2022 parliamentary election, Macron's candidates won five of its six constituencies. In the 2024 European Parliament vote, the RN won 28.57% in Morbihan, below its national tally of 31.37%, but well above the 18.05% Macron's ticket garnered there.

Voters in La Trinité-sur-Mer, a handsome Morbihan seaside town were RN patriarch Jean-Marie Le Pen was born, seemed receptive to de Kersauson's pitch.

The 74-year-old used to summer with Le Pen's children when they visited the town, and joined the RN in 2021 at the request of Marie Caroline Le Pen, Marine Le Pen's older sister.

After he was convicted of financial crimes at two funds he ran and fined 50,000 euros, de Kersauson came fourth in the 2022 legislative vote, but was now optimistic about his chances.

De Kersauson believed Le Pen and 28-year-old party leader Jordan Bardella have softened the RN's image, and said he was disgusted by antisemitism.

Bardella was swift to say he no longer supported Martin's candidacy - but days later he remains on the party's ticket.

Martin said his tweet, first reported last week by the Liberation newspaper and picked up widely online, had been taken out of context and was not antisemitic. He said he was "in full campaign mode" and expected to win.

'NEW RIGHT'

De Kersauson said Morbihan voters were driven by cost of living concerns and anger at the president.

"It's not what we propose that brings them to us, it's the rejection ... of how Macron treats this country," he said.

Macron on Monday warned the policies of his far-right and hard-left opponents could lead to "civil war". He has conceded that his risky snap election call could backfire, but said it was needed to give greater clarity to French democracy.

Richard Martenot, a 24-year-old chef, called the RN a "new-right" party, revitalized by Bardella. He said it wasn't hard to find a job - Macron has taken unemployment to near its lowest level since 2008 - but pay was bad, and renting or buying a house impossible. He lives with his grandparents.

Charlotte Briand, a real estate agent in the nearby town of Savenay, said rental prices had more than doubled since 2018, pricing out locals.

Stephanie Le Roux, who moved to Savenay from Nantes in 2018 in search of cheaper property for her growing family, said she did not want to vote for extremist parties, but was bitterly disappointed by Macron.

"The far right will make promises that aren't necessarily achievable," said the teacher, 39. "But they are at least making promises. So people here think, why not?"

Matthias Tavel, the candidate in Savenay for the New Popular Front, a leftist alliance polling second, is running on an anti-Macron, anti-RN ticket. He said Macron's rightward drift, ostensibly to neutralize the RN, had made it more mainstream.

Also out campaigning in Savenay, Gauthier Bouchet represents the new face of the RN. The 36-year-old, who joined the party when he was 19, said he had witnessed a growing acceptance of the far right from a middle class angry at "neoliberal" Macron and wary of the "woke" left. He said Bardella had been instrumental in luring younger voters.

"We represent their interests, we look like them, our candidates, most notably Bardella, speak like them, and it's quite different from what's on offer from other parties," he said.

A short drive away in the shipbuilding city of Saint Nazaire, a blue-collar town that has long been a leftist bastion, the RN came second in the European elections, less than 2 percentage points behind the Socialists.

In his office, covered in General Confederation of Labour (CGT) posters, union chief Damien Girard said unions were losing the battle of ideas to the far right.

"The CGT has a bit of an old fashioned image. It's seen as your grandfather's union," he said. "The language of the unions isn't necessarily one recognized by young people."

(Editing by Janet Lawrence)

By Gabriel Stargardter