Résumé : Categorization, that is, any sociocognitive process that produces order (in the form of classification, hierarchy, comparison) between diverse or even disparate things (Jenkins, 2000), mobilizes a plurality of actors and institutions over time and space by establishing “borders” as a legitimate object of analysis (Lamon and Molnár, 2002). The categories relating to work and employment (whether legal, economic, administrative, etc.) are defined in a variety of ways, often in contrast to each other, while helping to structure social relations and determine power relations (Zimmermann, 2001). [premières lignes]