The new law states primary and junior high students have to keep their phones in backpacks or otherwise out of sight
French president Emmanuel Macron has come good on one of his campaign promises and banned the use of mobile phones in primary, junior and middle schools - both inside the classroom and even outside in the school playground.
Children will be allowed to bring their phones to school, but are not allowed to get them out at any time until they leave, even during breaks.
Up until now, allowing mobile phones in schools was down to individual establishments.
In schools where mobile phone were banned, teachers say it has made a difference. But pupils disagree saying it hasn't changed must in the classroom.
Phones were already forbidden during classtime in France, but with the new law primary and junior high students have to keep their phones in backpacks or otherwise out of sight.
But the law does not state any specific punishment for their use, and lawyers says teachers do not have the right to seize non-dangerous belongings from students.
In France, figures show nearly 90 percent of children aged 12-17 own a smartphone.