PARIS — Young women marched in London last month in memory of Sophie Lionnet, a young French au pair who had been murdered and whose charred remains were discovered on Sept. 20 in her employers' backyard. The au pairs were also protesting their own living and working conditions, the endless hours and the feeling of exploitation.

Every year, thousands of mostly young women travel abroad to work as au pairs, taking care of local families' children and receiving food, housing and some spending money in exchange.

It is hard to estimate how many au pairs there are; every placement agency has its own statistics. But many young people choose to bypass agencies, to avoid paying fees. Some do not even have written agreements on work hours or pay. These situations often lead to abuse. Horror stories abound on social media platforms for both French youth abroad and foreigners in France.

Caroline Gandilhon, a student from the Val-de-Marne area southeast of Paris, was very happy with her first experience as an au pair in England. Her employers, whom she had met online, treated her like a member of the family, she took care of an "adorable" baby and she was paid 80 pounds ($105) per week.

She said her next family, also found online, was very different and did not respect their agreement. Instead of a large room with a private bathroom, as she had been promised, the young French woman lived in a "closet" with a "rundown toilet." She said she was given many household chores. "The parents didn't want me to leave the house during the day except to go grocery shopping, and they asked me to stay home during the weekend in case they needed help with the kids. In short, I was a little exploited," said the young woman. "The kids hit me and insulted me." She decided to leave after only one month.

At first, everything was going well

Lauryn, who also left for England without a contract or an agency, saw her situation deteriorate bit by bit. "At first, everything was going well," but one night, her host family woke her up at 10:30 to polish shoes. And "as the days went by, they added things for me to do," such as ironing or cleaning the entire house, tasks that were not part of the responsibilities she had initially agreed to.

In France, many young foreign women feel they are abused by their host families. "They exploited me. I had to spend all day taking care of a baby and then go pick up the 5-year-old son, and on top of that I had to clean the house, do the ironing, all for 45 euros about $52 per week," said Andrea, who is from Barcelona. Another young woman was locked in the house by her host family.

Lucía Pérez, 22, says she suffered an "ordeal." She found a family online who was looking for someone five hours a day, four times a week. They said their house was "easily accessible" with public transportation, when in reality, a bus came by only once every hour and a half. "I worked day and night," the young Spanish woman said, especially since one of the children was handicapped and not in school. Pérez, who didn't have a contract, ended up filing a complaint.

At least one full free day per week

For Sophie Hertzog, president of the French union of au pair agencies, it is impossible to verify the seriousness of host families online. "In fact, some countries, like the United States, only allow au pair placement through agencies," she said.

But the rules vary and are often vague. The European Agreement on au pair Placement of 1969, signed by several countries, set up an initial framework. It specifies that people placed as au pairs must be aged between 17 and 30 and must have a written agreement with the host family that includes food and housing. The au pairs must also be given "at least one full free day per week," including one free Sunday a month, not work more than five hours per day, etc.

Britain is not subject to this agreement, unlike France, where foreign au pairs benefit from a "family aid trainee" status. Hertzog still considers this status ill-defined: "When they apply for a visa, they get a student visa. We want them to have a clear status, because these youths are coming first and foremost for a cultural exchange."

In France, host families must support and declare their trainees. But many au pairs fly under the radar. The URSSAF, the French organization that collects social security contributions from employers and employees, counted only 1,700 employers of "family aid trainees' in 2017. This is low, according to placement agencies. Hertzog estimates that there are between 4,000 and 5,000 au pairs in France.