This study, adopting a qualitative approach to political communication, looks in depth at the way Twitter is used as a PR tool by five French politicians. It suggests that the microblogging service plays a specific role in allowing them to monitor public opinion and current affairs, to interact with voters, journalists, stakeholders and other politicians and to disseminate information. The way politicians use Twitter is influenced by concerns of impression management (content and style of tweets), and also various institutional, political and social/symbolic limits, which contribute to reveal tensions between the field of French politics and the way it has shaped traditional political communication practises on the one hand, and the technical and social characteristics associated with Twitter on the other. While these characteristics may be factors encouraging politicians to adopt the microblogging platform as a PR tool, they also constitute challenges in terms of PR.