Jean-Marie Le Pen (L), the founder of France's National Front party, reacts with his granddaughter Marion Marechal-Le Pen after she won a seat in the run-off round of the legislative elections in Carpentras June 17, 2012. REUTERS/Jean-Paul Pelissier

The new poster girl for France's far right National Front (FN) is a blonde pin-up with angelic features, who became the youngest ever deputy in the National Assembly on Sunday at the age of 22.

Marion Marechal Le Pen, granddaughter of FN founder Jean-Marie Le Pen, was confirmed as the party's brightest new star after winning one of only two seats picked up by the anti-immigrant, anti-Europe FN in the country's parliamentary runoff.

Her victory in the southern town of Carpentras, along with that of lawyer Gilbert Collard in the nearby Gard region, mark a return by the FN to parliament after more than two decades.

The fourth-year law student, who was given the nudge to run by her grandfather, was left carrying the Le Pen torch after her aunt was beaten by a whisker in the northern town of Henin-Beaumont.

FN leader Marine Le Pen went down to the Socialist Party's Philippe Kemel, winning 49.9 per cent of the vote to his 50.1 per cent.

Marechal-Le Pen scored a smaller proportion of the vote in Carpentras, an FN stronghold, but her 42 per cent was enough to get her elected in a three-way race against a candidate from the centre-right Union for a Popular Movement and a Socialist.

Jean-Marie Le Pen, who had considered running in Carpentras but decided in the end to defer to his granddaughter, was clearly delighted at the party's win in a town where the party was wrongly accused in 1990 over the desecration of a Jewish cemetery.

“The National Front wants to avenge what happened in Carpentras through this young girl, who is a symbol of her generation,” he said, announcing her candidacy in April.

Celebrating his progeny's win on Sunday the 84-year-old provocateur said his granddaughter was “de bonne race” (well-bred).

Marechal-Le Pen said she was “proud” of her family but firmly rejected accusations of being a “marionette” (puppet), who was pushed into politics as part of a strategy to give the FN a softer, more attractive face.

Spearheaded by Marine Le Pen that strategy has seen the party's support surge among young people and women, confirming the FN as France's third-largest political movement.

“I'm not here to look good,” Marechal-Le Pen defended Sunday. “I'm carving out my own path.”

In an interview with French television during her campaign, she described how growing up with Le Pen in her name - “the insults, the lack of understanding, the rejection at school” - had prepared her for the rough and tumble of politics.

After failed attempts to win seats in Paris in municipal and regional elections in 2008 and 2010 regional elections she found fertile ground in Carpentras, where Le Pen won her highest score nationally in April's presidential election - 31.5 per cent.

Marechal-Le Pen says she fully subscribes to the FN's programme to “drastically limit” immigration and build trade barriers around France.

Above all, she wants people to take her seriously.

“This election will change my life,” she admitted while warning: “I don't want to become an attraction for gossip magazines.” - Sapa-dpa