ISBN : 978-2-87463-228-0International audienceAfter having stated some definitions and specified the legal and tax status of nonprofit organizations in France and the USA, this paper begins by comparing the scope of the American and the French third sectors, their structure and resources, using data from the Johns Hopkins Comparative Nonprofit Sector Project. It explains the differences between the two sectors, which are considered to follow the Liberal Anglo-Saxon and European Welfare Partnership ideal-types found in “social origins” theory. Secondly, the paper highlights the evolution of the two sectors from 1995 to 2007. It stresses the reinforcement of the specific features of third sectors, and their path dependency, even if some trend...