Ms. Sonnet, the O.E.C.D. economist, said that high youth unemployment is a regular problem in France. Companies are afraid to commit to permanent hiring when economic growth is stagnant and charges for social benefits are so high, and the educational system tends to value liberal arts over technical or industrial expertise.

They “often don’t learn the skills that employers need,” she said. “They’re simply not ready to work.” Ms. Sonnet promotes more use of apprenticeships, as in Germany, where students work part time while they go to school.

François Béharel, the president of Randstad France, a branch of the multinational employment agency, said that the problem of youth unemployment among the educated is worsening at a time when employers are crying out for engineers, computer technicians, electricians and welders.

“We have to begin with parents — ‘Stop dreaming of white collars!’ ” Mr. Béharel said. “Blue collars, there really is a true path for them,” he said. But small and medium-size companies, which are France’s primary employers, do not have the resources or the profit margins to train the untrained.

“We’ve piled up battalions of students in general education, and everyone knows that there aren’t 10,000 among them who are going to find the job that they imagined when they entered university,” he said. Only 40 percent of students entering university get their degree; the rest drop out, trained for nothing.

Still, he said, a college degree is the best path to a job — only 10 percent of those with diplomas are unemployed after four years, while 40 percent of those without diplomas are jobless. But the passage to finding that job is now longer, costly for the person and for the state. It also delays marriage, house ownership and retirement.

Ms. Forriez is friendly and resourceful, with a small gap in her teeth that the French call “les dents du bonheur” — the teeth of happiness. But staying happy is also a job. “You tell yourself that you went through a lot of trouble to pay for your studies,” she said. “It’s hard, and in the end you think: ‘Here I am. I did five years and made a lot of sacrifices, and for what? To make new ones, because I need money to live.’ ”