Along the winding roads of Yonne, one of France’s poorest and most sparsely populated départements, Marine Le Pen’s smiling face is now part of the landscape.

Strictly speaking, fly-posting is illegal. But in the villages of flint houses and conical-roofed chateaux surrounded by fields of yellow rapeseed blooms, some of Le Pen’s young foot soldiers have been busy ignoring the law and threat of a €9,000 (£7,694) fine.

The Front National leader has an army of similarly motivated young people across France who, opinion polls suggest, are turning away from its traditional parties towards the far right.

Analysts believe that up to a quarter of this generation, who never knew the antisemitic, racist, Holocaust-denying rhetoric of the Front National founder, Jean-Marie Le Pen, are ready to vote for his youngest daughter.

“We are mobilised everywhere. We are determined. We have energy. I have one aim: to get Marine Le Pen into power,” says 16-year-old Alexandre Schwager, handing out political leaflets at the spring fair and farmers market in the town of Toucy.

Schwager and Marie Buzzetti, 20, a student nurse, are stationed outside the town hall. Supporters of hard-left rival candidate Jean-Luc Mélenchon are a few metres away, while the team campaigning for Le Pen’s closest rival, Emmanuel Macron, are down the street next to the monument to Pierre Larousse, the creator of the first Larousse dictionary and the Burgundy town’s most illustrious resident.

“Young people have tried the traditional left and right parties and we feel nothing was done for us. So we’ve looked for an alternative,” says Buzzetti. Asked which aspects of Le Pen’s anti-immigration, anti-Europe, “France first” programme she particularly agrees with, Buzzetti does not draw breath. “All of it,” she says. “It all makes sense to us. And for me the Front National is the only party that is concerned for all of France, the whole population, including those in the poor rural areas.”

Olivier Anest, 24, who works for the local radio station France Bleu, adds: “We’re the only party that goes into the poorer areas. When we speak to people there, they tells us they never see any of the others.”

Yonne is part of what Le Pen’s party calls “forgotten France”. Political analysts and journalists refer to it as La France péripherique, a mythical zone less than two hours by train or car to Paris, but excluded from the benefits and riches offered by the capital.

More than half of the department’s population work in agriculture, which goes some way towards explaining why the unemployment rate is about the same as the 9.6% national average. For the under-24s, however, many of whom leave school with no qualifications, the unemployment rate rises to just over 26%. They feel “lost and ignored”, says Anest.

Journalist Charlotte Rotman spent 18 months talking to young people prepared to not only vote for the Front National, but campaign for it. The result was a book called 20 Ans Et Au Front, published in 2015. “I found certain lines had been crossed. It was no longer taboo to be with the Front National, it was no longer something you did on the quiet.”

Rotman says Le Pen’s party also encourages the young to dream of a career in politics without having to go through an elite grande école or spend 30 years climbing the party ranks. “What the Front National does well is to welcome the young and value them. The other mainstream political parties look down on the young, but it promotes them. You can be 22 and head of an electoral list. The party has developed a catch-all dynamic. It appeals to people who are from all backgrounds. With or without qualifications, working class and bourgeois.

She adds: “Even those who benefited from globalisation, world music, travel, found the Front National’s tough lines on closing borders and xenophobia spoke to them.”

So acceptable has it become for students to support Le Pen that the prestigious Sciences Po institute in Paris, occupied for 47 days during the May 1968 student riots, recently saw the establishment of its first Front National student group.

The growing attraction of the far right to the young first caught France’s attention in December 2015, when pollster Ipsos declared that most young voters had abstained in the first round of regional elections, but of those who had turned out, 35% voted for the Front National.

Sylvain Crépon, a sociologist and specialist on the far right, told Les Inrocks magazine: “They’re often youngsters with no or few qualifications, thus weakly armed to confront globalisation and the European construction. They have little confidence in government parties and a strong pessimism for the future.

“Young people voting Front National do so because they are entering the job market at a time of a job shortage. The Front National proposes a closed society, protectionist, that speaks to this population that is tempted to turn in on itself.”

Elsewhere, young voters are associated with social and cultural liberalism, tolerance and openness. But the mood of French youth has darkened steadily as they have seen their hopes and status eroded by unemployment.

In Toucy, Julien Odoul, 31, is rallying his pamphlet-wielding Le Pen troops. Smartly dressed in the Front National uniform of dark jeans, a tailored suit jacket and an impeccably pressed white shirt, he is head of the party in Yonne and will stand for parliament in the legislative elections that follow the presidential vote on 23 April and 7 May. The oldest member of Odoul’s executive bureau is 44.

Just over 36% of Yonne’s 342,000 inhabitants took the Front National to victory in the second round of the 2015 regional elections. “Yonne is typical of forgotten France: public services are disappearing, schools, post offices, gendarmeries are closing, which gives a sense of insecurity. There are zones where internet or mobile phones don’t work, there’s a shortage of doctors and a drop in people’s life expectancy,” Odoul says.

“The young are extremely realistic. They see the world around them and the difficulties they have and are rallying to the Front National. Other political parties promised a radiant future, but all the young see is unemployment, precariousness and lawlessness, so they are disenchanted.”

Edwige Jacquet, 34, whose day job involves organising cultural events, is also standing as a Front National candidate to the national assembly. “Today, young people are less afraid to say loud and clear they are voting Marine Le Pen. They’re looking at the other candidates, they’re looking at the dramatic state of the country, and they are waking up,” she says.

A few metres away, Alain Raymont, a retired adult careers adviser, is campaigning for Mélenchon, currently fourth in the polls behind Le Pen, Macron and conservative François Fillon – and in front of the Socialist candidate, Benoît Hamon.

“Sad to say there is a problem for youngsters whose situation is very difficult, whose generation has become poorer and who study hard but spend years trying to find stable employment,” Raymont says.

He perks up: “But not all youngsters are turning to the Front National. A group came to me the other day and offered to go campaigning for Jean-Luc Mélenchon. We’re feeling our own dynamic. There’s two weeks to go to the election and we’ll just have to see what happens.”

Back with the Front National, however, Schwager, the son of a gendarme, is quietly optimistic that Le Pen will win the presidential election. If not this time, then next.

“The door is open. She is succeeding here because she is the only person who bothers about all of us,” he says.

Kim Willsher in Toucy