The grant will be given to women after the birth of their third child for one year only. Mothers will receive monthly payments up to a maximum of 2750, around 530. Payments, linked to parents' salaries, will start from 1 July 2006.
The move aims to redress the falling population in France and the trend among middle-class professionals to start families later and have fewer children.
The French birth rate is 1.9 children per woman, which, although the second highest in Europe after Ireland, is not enough for a stable population, which requires a birth rate of 2.07 children per woman.
In the UK there are 1.6 births per woman and the European average is 1.4.
French Prime Minister Domnique de Villepin also pledged a further 15,000 places for state-run or approved creches for children under three. Tax credits for childcare costs for under-sixes will also double.
