Urban unit zoning in 2020

This document is the companion for the dissemination of the urban units in France. Urban units are built up from neighboring municipalities, based on the continuity of the built environment and the number of inhabitants. This document focuses on concepts, datasources, decision rules that led to the 2020 version of urban units definition and highlights the differences with the 2010 version.

Detailed presentation of concepts and methodology is given in part 2. This comes after some historical considerations and comments on possible uses. It is followed by a statistical summary of urban units and some evidence of its robustness.

Urban unit zoning is the oldest statistical zoning. It was introduced for the 1962 census, following a pilot study on the agglomeration of Paris and recommendations from the Praha 1959 Conference of European Statisticians’ Recommendations. Definitions has little evolved since, still based on the continuity of the built environment and the number of inhabitants.

An urban unit is defined as a municipality or group of municipalities with a continuous built-up area (no more than 200 metres between two buildings) with at least 2,000 inhabitants and some additional criterion related to population. In particular, a municipality must concentrate more than a half of its population in a continuous built-up area of the urban area (see 2.3).

Various studies and data are using this zoning, which exists in many other counties (in Europe but also in Brazil (áreas urbanizadas) or in the USA (urban clusters). Everyone should keep in mind that urban units have been built for statistics and have no legal effect, as the highest French administrative court (Conseil d’État) states in December 1996 in its decision n°165061.

2020 urban unit zoning was published in October 2020 on Insee’s website. There are 2 467 urban units, 8 % more than in 2010, and 79 % of the French population lives in these units.