Reiterating the need to build mutual trust and confidence and to promote effective implementation, Article 13 of the Paris Agreement established an enhanced transparency framework for action and support. The purpose of the transparency framework of action is to provide a clear understanding of climate change actions taken by countries in light of the objectives of the Convention, including clarity and the tracking of progress towards achieving Parties’ individual NDCs. This framework is thus one of the central pillars for enhancing information on NDC implementation and raising the ambition to meet the Paris Agreement’s goal of staying well below 2 degrees.  Decision 1/CP.21 states that the modalities, procedures and guidelines of this transparency framework are to build upon and eventually supersede the measurement, reporting and verification (MRV) system established under COP-16 in Cancun and COP-17 in Durban. The existing MRV arrangements agreed during these COPs will thus form the basis for the new enhanced transparency framework. This publication feeds into the UNFCCC discussion on international reporting to track  progress in implementing NDCs. It aims to enhance the knowledge of policy-makers and  decision-makers in developing countries by identifying and explaining the reporting requirements established under the Paris Agreement. Though the new transparency framework will apply to all countries, the publication focuses on transparency regarding developing countries’ mitigation contributions. Adaptation and finance are also important elements of the new transparency framework, but they are not covered in this publication.