Vulnerability is a polysemous, multiscalar, multidimensional notion (Nathan, 2009 ; Janin, 2008 ; Léone, 2007 ; Bogardi, 2004 ; Bohle, 2002 ; Fabiani, Theys, 1987), far from the simple identification of the social traditional criteria as the age, the gender, the social status or the level of income (Birkmann, on 2006). In France, it is not yet a sociological concept applied to environmental issues, whereas somewhere else the researchers, in particular American or Latin American, work on this problem since around thirty years. This article clarifies the route of paradigm of the social vulnerability in the study of the environmental risks. It presents first a review of its definitions and uses by the social sciences. It secondly exposes some scientific questions for which the notion was mobilized by sociologists. Lastly, we analyze the stakes and the challenges of this new paradigm for the contemporary sociology.