In many countries, including France, the non-take-up of social services is a subject of increasing attention, which is reflected in the production of statistics or the development of specific actions. It meets a strong interest from several actors, partly for its capacity to offer a critical and renewed look on the evolutions of the social protection system. However, the popularity of the fight against non-take-up comes at a time when reforms make access to social systems more complex and/or reduce the scope of social rights, which places it at the heart of the ambivalence of the social state.