As the COP 21 conference opened, the Louis Bachelier Institute published a French & English compilation of the policy article "Negotiating effective institutions against climate change" written by TSE researchers Christian Gollier and Jean Tirole. The authors propose a roadmap to an international negotiation process, urging negotiators to go back to the basics: the need for a universal, international carbon price, a measure and control mechanism as well as a governance system accepted by all.