Fontainebleu, France - When twelve million French children return to school in early November after a two-week holiday, several thousand others will stay home because their parents have opted out of a system they claim no longer adequately teaches basic skills.
Home-schooling in France remains marginal compared to other countries.
In the United States five percent of school-age children -- more than one million -- are educated outside of schools, many on religious grounds, according to the US Census office.
And in Britain about 50,000 kids hits the books at home, almost half of them because of bullying by classmates according to Mike Fortune-Wood, author of "The Face of Home Education in the UK."
In France, which has always prided itself on the efficacy and quality of its highly centralized school system, home-schooled kids number less than 20,000, not counting another 40,000 children who study outside of school in state-run programs due to illness or careers in sports or music.
But a decade ago there were even fewer, and the rapidly growing number of stay-at-home children is seen by many as a warning sign about the health of the public school system.
At the beginning of this year, then education minister Francois Fillon told the parliamentary committee on education that "80,000 children start secondary school without really knowing how to read, write or count."
That is the main reason "parents who decide to homeschool their children," said Catherine Jousse, director of the Cours Hattemer distance-learning department. "And they are not all city dwellers from the upper echelons of society -- far from it. But they want to give their children a better chance."
Jean-Claude Marcel of "Les Enfants d'Abord" (Children First), an association of 400 home-schooling families, said that although French law allows home-schooling "most French people don't know they have this choice."
If the education ministry says home-school numbers have stayed level in the past five years, correspondence schools claim they are soaring.
The Cours Sainte Anne primary school, founded six years ago with a handful of students, now has 800. Patrick Isnard, director of the 15-year old Cours Pi said he has 1,800 students "and the number grows exponentially every year," while Marc Gracia, director of studies at the Cours Valin, said his student body is growing by "10 to 20% annually."
The government keeps a close eye on children who opt out of a formal teaching framework, to monitor progress and to guard against cults.
Those on correspondence courses are considered to be in full-time education and are left to get on with it.
Home schooling can hurt financially. Correspondence courses cost from 330 euro to nearly 2,000 euro a year whereas public school is free. As Catherine Chemin, vice president of CISE (Choosing to educate one's own child), pointed out, "it's generally the mother who gives up her job to stay home and teach" adding that in her own case "we certainly would have a better standard of living if we both worked ."
Gracia noted that "many of our students are the children of teachers," a phenomenon also noted by the other schools. Marcel of "Children First," an ex-teacher, said "I did not want to put my children through school after seeing it from the inside."
Another teacher, who requested anonymity because he is still working in a public school, withdrew both his daughters two years after he began teaching. "My experience is that close to 50 percent of young secondary school pupils don't know how to do basic arithmetic," he said.
He signed his children up in a correspondence school instead. "I'm much happier with the level there than with the one I see every day at the school I work at," he said.