This report analyses how the role of sustainable development can be strengthened in the process of further designing the mechanisms under Article 6 of the Paris Agreement. The paper reflects on the experience with sustainable development in past and current market mechanisms and describes to what extent countries agreed on sustainable development issues in multilateral instruments and institutions outside the UNFCCC. Based on the current negotiating draft texts (SBSTA 50 from June 2019, as well as CMA2 from December 2019), recommendations are put forward on how to anchor sustainable development and safeguarding provisions in the rules for Article 6.