Defines the extent of a city’s influence on the surrounding municipalities. An area is a group of municipalities, in a single block and without enclaves, consisting of a population and employment centre and the surrounding municipalities in which at least 15% of the working population work in the centre. The most populated municipality in the centre is called the central municipality.
The centres are determined mainly on the basis of density and total population criteria, following a methodology consistent with that of the european degree of urbanisation. An employment threshold is added so as to avoid that mainly residential municipalities with only few jobs are considered as centres. If a centre sends at least 15% of its workforce to work in another centre at the same level, the two centres are combined and together form the heart of a functional area.
Municipalities that send at least 15% of their workforce to work in the centre form the commuting zone of the centre's functional area. The definition of the largest functional areas is consistent with the definition of "cities" and "functional urban areas" used by Eurostat and the OECD to analyse the functioning of cities. The functional area’s zoning thus facilitates international comparisons and makes it possible to visualise the influence in France of large foreign cities. Thus, seven areas have a city located abroad as their centre (Basel, Charleroi, Geneva, Lausanne, Luxembourg, Monaco and Saarbrücken).
The areas are classified according to the total number of inhabitants in the area. The main thresholds used are: Paris, 700,000 inhabitants, 200,000 inhabitants and 50,000 inhabitants. Areas whose centre is located abroad are classified in the category corresponding to their total population (French and foreign).
The 2020 functional areas zoning (ZAAV) replaces the 2010 zoning in urban areas (ZAU).