PARIS is structured in 7 work packages (WPs). The WPs are designed based on the following principles:

• An iterative process of knowledge exchange is required between national inventory agencies and the PARIS team to generate maximum benefit to inventory compilers. 
• Rapid progress can be made by engaging stakeholders with an early focus on F-gases, which have relatively simple sources, and using these case studies to highlight the benefit of top-down estimation to inventory compilers. 
• Improved attribution of top-down fluxes to source or sink sectors is required to generate comparisons that are most useful to inventory compilers. 
• A subset of countries should be investigated in detail and should comprise a range of expertise, from mature inventory evaluation programmes to those aspiring to build up inventory evaluation infrastructure 
• Innovations should complement and add value to ongoing major programmes such as the European Centre for Medium Range Weather Forecasts Copernicus Atmosphere Monitoring Service (ECMWF CAMS