A bit old, but still

Several evaluations suggest that policies that provide financial support to families or paid leave at the time of childbirth have a positive, but rather limited, impact in fertility. Of all the policies introduced over the years, provision of childcare services appears to be the most effective in encouraging families to have children and women to remain in the workforce.

French family policies provide a diversified system of supplementary resources in the form of money, time and services needed to raise children. The State provides support to diversified types of families with children at ages from early to late childhood. Another key ingredient has been the high stability of family policies, based on strong popular support. This stability gives confidence to families that they will benefit from continuous support from the birth of a child until entry into the school system and beyond. Such confidence creates a favourable environment for the decision to have children

https://www.un.org/en/development/desa/population/events/pdf/expert/24/Policy_Briefs/PB_France.pdf

Ménage à trois probably.

Hmm, I was thinking "well, that's an improvement, but still too high".