The report summarizes key lessons learned from the Kyoto Protocol’s Clean Development Mechanism (CDM) and Joint Implementation (JI) for the new Article 6.4 mechanism of the Paris Agreement. The report first provides an overview of the issuance and use of carbon credits under these mechanisms. This is followed by an assessment of what elements of the existing mechanisms could be transferred to the Article 6.4 mechanism. We recommend that mitigation activities under the Article 6.4 should be considered ‘high-hanging fruits’, enhance ambition, have a high likelihood of additionality, provide co-benefits for other sustainable development targets, and ensure that emission reductions can be reasonably attributable to the mitigation activity.