Article L2242-1 of the French Labour Code
In companies where one or more trade union sections of representative organisations have been set up, the employer shall initiate negotiations at least once every four years: 1° Negotiations on remuneration, in particular actual salaries, working hours and the sharing of added value within the company; 2° Negotiations on professional equality between women and men, including measures to eliminate pay differentials and the quality of life and working conditions.