The PhD dissertation studies new digital participative technologies called "civic apps", applications for mobile and web developed in response to a large scope of public problems and based on the principle of crowdsourcing. The research focuses on the conception of these tools, their usages and the way these tools transform the communication among citizens and between citizens and public administrations. It also explores new formats of civic tech innovation, such as civic hackathons, and question the usage of programming code as a new tool of collective action.The thesis calls upon the methodologies of sociology of science and technology, sociology of public problems, political science and science of information and communication. Based on ...