Article L1225-54 of the French Labour Code
Half of the period of full-time parental leave is taken into account in determining the employee’s seniority rights. When an employee reduces his working hours as part of parental leave, the period of part-time parental leave is treated as a period of actual work for the purposes of determining the employee’s seniority rights. The employee retains the benefit of all the advantages acquired before the start of the leave.