Non-hazardous engineered landfills (ISDND) are a recognised source of methane emissions — a short-lived but highly potent climate pollutant. According to the national inventory, landfills account for 75 to 81% of GHG emissions from the waste sector (around 12 MtCO₂e/year), compared to roughly 6 MtCO₂e according to industry estimates.

This information paper, produced with Citepa, examines the main methodological limitations behind these discrepancies — landfilled waste composition, the IPCC decomposition model, and methane capture data — and presents ongoing work to improve knowledge of sorting-refuse composition, led by Citepa in partnership with ADEME, FNADE and the French Ministry for Ecological Transition.