The legal analysis of the COP 21, its results and prospects they open proposed in this paper is done according to a standard of transparency, in the context of a complex governance, that the theory of global administrative law aims to better understand. This assessment shows that the balance between transparency and opacity, intelligibility, effectiveness or efficiency is both delicate to establish and unstable. If the way the cursor was positioned under the Paris Agreement may seem unsatisfactory, it must not be forgotten that it is intended to evolve.