Prospective analyses, be they in the field of transport or other areas, are generally developed based on a retrospective of the preceding decades. The trends highlighted are then followed, changed, brought out, accentuated, etc. However, a recent look at mobility behaviors and how they are evolving (for example, the speed with which bicycle use has made a comeback in densely-populated cities is instructive in this regard), and at recent societal changes (particularly as regards the development of Information and Communication Technology [ICT]) suggests the need for methods that better reflect behavioral changes by being more attentive to weak signals relative to mobility. The goal of this article is to offer a prospective view for France in 2050. The analysis was funded by SNCF in preparation for the Paris Climate Conference (COP 21). Our main objective is to demonstrate and discuss an original, 4-step prospective analysis method. Phase one - the diagnostic phase - is based on a review of scientific and gray literature from the past five years and a quantitative survey of a representative sample of the population (in France). For this, we surveyed 1800 persons aged 15 and older by telephone. In phase two - the staging phase - key changes in mobility behaviors (on which the prospective scenarios were built) are highlighted. Phase three explores the various figures. Once the main lines of the scenarios have been sketched, the modal shares and associated energy consumption is determined. The objective of this prospective work is highly political, given that these figures are intended for use in planning policy that is both realistic (taking into account current infrastructure and service offerings, and their capacity for change) and readable (positioning relative current situations abroad). The fourth and final stages establish a political agenda with concrete actions for the short, medium and long term. In this article we describe the first three stages, systematically explaining our choices. We take stock of the current situation of human mobility by interpreting the latest trends described in the literature and the results of the quantitative survey. We then describe the three resulting scenarios ? ultra-mobility, altermobility and proxy-mobility ? explaining in detail the hypotheses upon which we built them, as well as the modal shares, traffic volumes and CO2 emissions associated with them.