This article analyzes how activists, rooted in the Free/Libre and Open Source Software (FLOSS) movement, interfere in European Union decision-making in order to advocate principles of freedom, openness, transparency, access to information, participation, creativity, and sharing. The analysis is based on a case study of a French activist group's campaign against the strengthening of copyright enforcement measures and for Net neutrality in the reform of the Telecoms Package-a set of five directives regulating the European Union's telecommunications sector. I discuss how free and open source principles sustain their action repertoire and claims during the campaign in the light of recent literature regarding Internet activism and the FLOSS movement.