Based on the latest knowledge available on the use of CBA in cycling infrastructures projects in Denmark and the Netherlands, the following analysis gathers information and aims to apply them to the decision-making process of cycle superhighways in France. After a detailed explanation of the context of mobility matters in France, two case-studies are presented so as to collect opinions on the process of implementing the above-mentioned infrastructure and analyse how to engage in a process of convincing and mobilizing the many stakeholders of the metropolises of Toulouse and Lyon, France. This project is grounded in academic literature about CBA, rational argumentation and empirical data about the positive aspects of cycle superhighways and confronts the political mechanisms in a rapidly changing context.