The implementation of PreParE on 1 January 2015 reduced the duration of compensation for parental leave from 36 to 24 months for families with two or more children since this leave is not shared between the two parents. This reform is likely to have changed significantly the behavior of families since compensation no longer covers the entire period from birth to entry to school. The objective of this research is therfore to evaluate the effect of this reform on parnts’ activity (by distinguishing between full-time and part-time parental leave), as well as on the use of different types of childcare, wages and fertility. CNAF data enable us to identify the causal effect of the reform since they cover all families receiving CAF family allowances. This identification is made possible by comparing families according to whether they gave birth to a second child or more in the month just before the implementation of PreParE and the month just after.