International audience"This article focuses on environmental activism and the uses of digital. The case study of the controversy around the EuropaCity project in the Parisian periphery is based on an analysis of the use of the social network Twitter. The corpus of collected and analyzed data corresponds to the hashtag of the controversy, #EuropaCity, as well as the profiles of the main actors of the debate on the platform. The results make it possible to establish a map of a debate that is struggling to be established online. More specifically, it is question of observing the evolution in time of the debate, by the temporal distribution of the tweets and its articulation with the actuality of the mobilizations, the evolution of the project ...