The magazine 60 Million Consumers (60 Millions de Consommateurs) has turned its attention to sprays and oils for the first time - and their findings aren't pretty.
Testers investigated 46 "so-called purifying products" - including ten top-selling sprays with essential oils.
"The verdict is that all of them contained undesirable substances," Christelle Pangrazzi, the associate editor of the magazine, told the LCI newspaper.
Products by La Croix, Fébrèze, and Sanytol were reportedly among those that didn't pass the test.
"Fighting pollutants and allergens in our homes has become a huge marketing tool for manufacturers. But these products don't purify homes like you're be led to believe - rather the opposite."
The oils and sprays contain Volatile organic compounds (VOCs) - organic chemicals that pose risks to people's respiratory system, the magazine found.
The substances in the sprays can also trigger asthma attacks, headaches, skin reactions, nausea and can even cause people to gradually become more sensitive to allergens.
Pangrazzi added that the sprays could be particularly harmful for children under the age of three.
And what's more - the sprays can pose potentially lethal dangers for cats.
Pangrazzi recommended that instead of using sprays, people should try to air out their house for 30 minutes a day (in off-peak hours in big cities) and to regularly clean the home.
"There's no reason to use synthetic products, it's just a waste of money," she said.
The full details of the study - including the names of the products tested - will be available in the April/May edition of the magazine.