This essay analyses the evolution of legal rules, questions of law interpretation, as well as climate and development policy effects of the Clean Development Mechanism (CDM) as a mechanism which is linked to state and company-level emissions trading (ETS) and combines transnational climate protection law with the promotion of renewable energies. The essential goal of the CDM is to provide opportunities for cost efficient compliance with the Kyoto Protocol targets entered by Annex I countries, and to assist developing countries in achieving sustainable development. Therefore, Annex I countries are allowed to achieve part of their emission reduction targets by conducting mitigation measures in developing countries. It turns out, however, that specific CDM projects are frequently questionable in terms of climate and development policy. This is also related to enforcement problems, which represent a variation of the common environmental law issue of the latent identity of interests of controllers and controlled ones. It is hence questionable whether the discussed and partly decided reforms of the CDM and the subsequent restrictions adopted by the EU are sufficient to address the underlying deficits. That implies, at the same time, a kind of exemplary governance analysis on the basis of important aspects of the ETS.