Developing robust city-scale greenhouse gas (GHG) emissions inventories is key to understanding the challenges to be dealt with and to track progress of GHGs over time. Many local and regional governments integrate and report their GHG emission inventories to set reduction targets, design mitigation plans, and track progress during and post-implementation. A combination of different data sets can help enhance the robustness of the inventories, such as using bottom-up data and combining this with disaggregated data from national inventories (to address data gaps). However, the use of satellite data and atmosphere models at increasing spatial resolution is also exciting. The focus of this workshop is on assessing how atmospheric observations, especially as part of the future Copernicus anthropogenic CO2 emissions Monitoring and Verification Support (CO2MVS) capacity, can support city-scale GHG inventories, with a discussion between experts and participants on new services to be explored in this regard.