This paper presents a new research project of EPFL REME that aims to assess the influence of firms on climate policy. Firms do not form a solid block of opponents to climate policy regulation. As they face different incentives towards climate policy their influence is rather controversial. We want to identify the groups of firms influencing climate policy making. Our key research questions are: Why do firms influence climate policy making? Who are the actors and groups influencing climate policy? And finally, how do firms influence climate policy making? This paper aims to discuss a preliminary research plan for this project dealing with Switzerland and a country of the European Union as two case studies.