"This article follows the major historical steps with respect to the protection of the child aged less than three years in France and in Canada over the course of a century. Analysis focuses first on the motives behind increased intervention by political leaders on behalf of the child; next on the protection of the welfare of the mother and child; and finally on the evolution of demographic characteristics, in relation with processes of social and geographic differentiation. A remarkable convergence is observed between the two countries, despite veritable differences in political pressures and actions, traceable back to certain common structural traits, and linked with emerging patterns of international exchanges favouring the modelling of a new culture regarding childhood." (SUMMARY IN ENG AND SPA)