This article focuses on the decline in the use of public transport in the context of the Covid-19 crisis in the Lyon metropolitan area, France. Using data from a web-based survey, supplemented by traffic counts and a qualitative survey, it explains this decline by the decrease in out of home activities such as work and the concomitant increase in teleworking, as well as by modal transfers. These explanations are tested by multiple regression models that include socio-demographic, residential, professional and attitudinal variables. It concludes with a discussion on the lasting of these changes and their implications for mobility policy.