The legislation aims to reduce stress among workers who feel pressured to be permanently 'on call'
French workers have won the 'right to disconnect' from work emails outside of office hours.
From tomorrow, companies with more than 50 employees are required to negotiate with workers to define the limits of their work-life balance.
The law follows a 2015 report commissioned by labour minister Myriam El Khomri that warned of the dangers of letting work responsibilities seep into employees personal lives.
French unions have overwhelming supported the new legislation, and have been pushing for action for years.
According to AFP, several large companies including Areva and Axa have already limited out-of-hours emails, sometimes cutting off email access on evenings and weekends.
Over one-third of French employees use devices to work after hours each day, according to a study published by research group Eleas in October.