I wrote this article with my colleague Juliana Pigey from the Urban Institute in Washington. It was presented at the Fifth Urban Research Symposium held in Marseille in 2009. A summary of this work figures in the minutes of the symposium, published by the World Bank in 2011 under the title Cities and Climate Change. It was the first time that I materialized my personal investment in environmental and climate issues. The paper identified the funding available for cities to invest both in adaptation and mitigation, and highlighted a certain discrepancy between the needs and the tools available to do so. It provided a number of propositions for the development of financing tools, how to reintroduce local communities into systems that largely ignored them, and establish incentive schemes in their favor. Finally, it recommended the creation of a specific funding mechanism for the most impoverished cities such as those in fragile states.