Every year, the start of the budget debate in France is an opportunity to ask a number of questions: How much is public spending on climate? What is this money spent on? Which actors, both public and private, are on the receiving end? And above all: how should this spending develop in the future? Many numbers have been produced in France over the last few years and it is easy to get lost in the shuffle. This is why we wrote this handbook. We have gathered the information that we consider most important and tried to highlight what we know, what we do not yet know, and the key debates in France that politicians will have to hold and where they will have to quickly find compromises.