A contradiction arises in anarchist and autonomist movements when anti-authoritarianism encounters the situated power relationships that emerge within any process of political organization. This thesis describes how this contradiction creates a link between the "formalization" of activist general assemblies and the "horizontality" of social relations among participants, as well as how this tension is performed in face-to-face interactions. Establishing a dialogue between French discourse analysis and linguistic anthropology, this project analyses the sociopolitical dimensions of linguistic reflexivity, examining how the interactional order of general assemblies is naturalized and denaturalized. During a four-year period of ethnographic research, I collected three kinds of data: a selection of written texts, notes based on direct observation, and the transcript of an assembly meeting in its entirety. The analysis of this semiotic material shows how the "horizontal-formalist interactional register" - by focusing on domination as access to public speech - transforms and displaces power relationships between participants during those assemblies without, however, abolishing them. At the same time, this register neglects other ways of wielding power through speech. The naturalizing force of the "horizontal-formalist interactional register" is challenged, however, by the fact that the components of the speech event are differentially valued within anarchist general assemblies. Conflicts over the value of particular aspects of the speech event produce and are produced by an ongoing historical process of contestation and evaluation among the different entities composing the anarchist movement, particularly surrounding the question of political organization. As a result of both the valorization of political reflexivity and the strong discursive heterogeneity of metapragmatic discourses about the assembly, practices that denaturalize the speech event remain possible