and the AAVs are thus strictly comparable to the FUAs. Before 2020, INSEE used another metropolitan statistical area, the aire urbaine (AU), which was defined differently than the AAV, but the AU has now been discontinued and replaced with the AAV in order to facilitate international comparisons with Eurostat's FUAs.

The functional area is a grouping of communes comprising a 'population and employment centre' (pôle de population et d'emploi in