This study evaluates the redistribution effects of income tax and of its family-related components in France and Germany. Particular attention is shown to the treatment of different-size families, given in particular Germany's acknowledgement of the long-term weakening of its birth-rate, which has brought family-oriented policies back to the fore. The French family quotient system is sometimes seen as an explanation for the higher birth-rate in France. In spite of seemingly very different structures, the German and French social-fiscal systems appear in fact quite close to each other The treatment of children in the German system confers tax advantages relatively similar to those obtained by the family quotient, in particular for the first two children. On the other hand the comparison does highlight some important differences: (1) the tax advantages obtained in the French system grow more quickly in step with income than they do under the German system and, therefore, have a lesser effect on the reduction of inequalities; (2) The benefits given by the French system for the third child are higher thanks to the additional whole-point on the family quotient. This study focused on income taxes including any family-oriented components thereof, which, taking into account the structure of the German system, led to taking into account the family allowance and family supplement for France. On the other hand, it ignored the existence of minimum revenue levels in both countries as well as a number of other allowances. Therefore it can be used neither to compare the whole of the redistribution systems of both countries, nor to reach any conclusions in terms of well-being.