[en] Created in 1961, the International Expert Centre on Air Pollution and Climate Change (CITEPA) is the French National Emission Inventory Agency. CITEPA identifies, analyses and disseminates data and methods on air pollution and climate change in particular emissions of air pollutants and greenhouse gases (GHGs). CITEPA has been entrusted by the French Environment Ministry with the task of developing the national inventories of air pollutant and greenhouse gas emissions, under the commitments of France, in the framework of the European Union (EU) and the United Nations (UNFCCC and LRTAP Conventions). CITEPA is a well-established pool of international experts collaborating with the European Union, the United Nations, the World Bank and other international bodies. CITEPA conducts techno-economic and forward studies in the areas of energy, industry, transport, waste, fluorinated gases, agriculture, land use and forestry (LULUCF). This document is the compilation of the 4 CITEPA's activity reports for the 2016-2019 period. Each report presents the Citepa missions and skills, the general technical and regulatory context of air pollution and greenhouse gases, the elaboration of national emission inventories, the strategic projects and missions of the year, the actions of communication and public information, the organisation and administration of the Agency, and finally the perspectives of the year to come.