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Report n°1: The new constraints of urban development
Measuring urbanisation in France
Urban units and urban areas
Two classifications have been produced by INSEE, reflecting two distinct approaches that are nevertheless linked: the first, that of urban units, refers to contiguous construction; the second, that of urban areas, aims to account for territories linked to the city, not by contiguous construction but by the volume of residents working in the city.
The urbanisation analysis therefore compare the data from either one of the two classifications at any time.
An urban unit is an agglomeration of inhabitants, defined as a group of dwellings such that none is separated from the nearest by more than 200 metres, and accommodating at least 2,000 people. If an agglomeration of inhabitants extends over several municipalities, the group of municipalities forms an urban agglomeration. If the agglomeration only extends across one municipality, it is an isolated city.
All municipalities belonging to one urban unit are regarded as being urban. Other municipalities are classified as rural.
A'centre' has been defined for each of the multi-municipality agglomerations. If a municipality represents more than 50% of the population of the urban unit, it is the only town centre. Otherwise, all municipalities with a population greater than half that of the largest municipality are town centres. Municipalities that are not town centres consist of the suburbs of the urban unit.
An urban area is a group of connected municipalities, with no enclosed territories, made up of:
- An urban centre, which is an urban unit providing at least 5,000 jobs
- A periurban belt composed of rural municipalities or urban units, of which at least 40% of the resident population in employment works within the remainder of the urban area (the centre or the municipalities within its influence).
INSEE's zoning into urban areas includes other elements besides the urban areas. Polycentric municipalities are therefore municipalities or urban units of which 40% or more of the active residents work in several urban areas, without this threshold being reached for one particular area. A polycentric urban zone is a contiguous group of several urban areas and the polycentric municipalities linked with it.
The predominantly urban area comprises all urban areas and polycentric municipalities.
The predominantly rural area is made up of all municipalities not belonging to the predominantly urban area. This zone includes both small urban units and rural municipalities.
Choosing a spatial classification for analysis purposes
When focusing on economic trends, the urban unit is a suitable framework of analysis provided that, apart from rare exceptions, the decision centres and, more generally, the jobs generated by the city are still mostly concentrated within this urban centre. This concentration remains largely effective, even if a trend towards periurbanisation of economic activities is observed in relative variation.
On the other hand, if the focus is on fairly recent demographic dynamics, the urban area may be preferred, since the urban unit is often too narrow a framework of analysis for certain cities.
The French situation according to the urban units classification
After the 1999 census, the urban population of France was 44.2 million people, which encompasses an increase of 2.3 million compared with 1990.
In total, France has 5,954 urban municipalities (677 municipalities have been classified as urban since the census, while 20 have become rural again), which represents 75.5% of the population in 18.4% of the territory.
| 1936 | 1954 | 1962 | 1968 | 1975 | 1982 | 1990 | 1999 | |
| Population (in thousands) | 41,813 | 42,705 | 46,425 | 49,712 | 52,592 | 54,335 | 56,615 | 58,518 |
| Urban | 22,120 | 24,456 | 29,370 | 34,834 | 38,351 | 39,861 | 41,898 | 44,197 |
| Rural | 19;693 | 18,249 | 17,055 | 17,878 | 14,241 | 14,474 | 14,717 | 14,321 |
| % of the urban population | 52.9% | 57.3% | 63.2% | 70.1% | 72.9% | 73.4% | 74.0% | 75.5% |
| Urban surface area (km2) | 36,516 | 41,142 | 48,743 | 68,880 | 76,281 | 83,352 | 89,649 | 100,041 |
Sources: Insee, Ined
The urban territory, the sum of all the urban municipalities, occupied more than 100,000 square kilometres in 1999, expanding by 10,000 square kilometres compared with 1990.
Over ten years, the urban population increased 5.5%. Only slightly more than half of this increase is due to the population growth in municipalities that were already urban in 1990. The other half arises from the incorporation of new municipalities, previously the most dynamic rural municipalities, because they are often close to large urban centres.
Between 1936 and 1999, the population of towns has doubled, increasing from 22 million inhabitants to 44 million, while the metropolitan population of France only rose by 40%.
In the previous period (1992-1990), the net migration for central towns was negative (-0.31), that of the suburbs was positive (+0.21), and that of the rural area was strongly positive (+0.67). In the last decade, only the net migration for rural areas was positive (+0.44), while those of the central towns and suburbs were -0.12 and -0.15 respectively. This reflects the fact that urban sprawl occurs outside the perimeters of areas with contiguous construction, and highlights the necessity of analysing the phenomena according to the second INSEE classification, that of urban areas.
The French situation according to the urban areas classification
Using the new 1999 delimitations for zoning into urban areas (ZAU - zonage en aires urbaines), 45 million people (77% of the population) live in one of the 354 urban areas, while 41 million people (73% of the population) lived in one of the 361 urban areas in 1990.
The urbanisation of metropolitan France is therefore continuing. In 1999, 3.8 million extra people were counted as living in urban areas (using the 1999 delimitations). On one hand, the population grew by 1.5 million within the limits of the urban areas of 1990, which illustrates the concentration of the population in the territories that were already urban or periurban, in other words, a polarisation phenomenon. On the other hand, 2.3 million people have been added through the geographical extension of urban areas between 1990 and 1999, thus taking urban sprawl into account.
So the cities are spreading further and further: the urban areas comprised 13,908 municipalities in 1999, compared with 10,687 in 1990, and covered 176,000 square kilometres compared with 132,000. The working population is mainly employed in the urban centres, though living further and further away, while the inner outskirts are becoming more densely inhabited. Some 222 periurban municipalities in 1990 had become an integral part of the urban centres in 1999, through contiguous housing, and more than one thousand polycentric municipalities in 1990 had been integrated into periurban municipalities by 1999. Furthermore, 4,916 municipalities belonging to the predominantly rural area in 1990 had become urban centre municipalities, periurban belt municipalities or polycentric municipalities by 1999, a phenomenon affecting 3.2 million people.
Urban sprawl is less noticeable today than it has been in the past, but perhaps more diffuse, with the population growth occurs in vast territories further and further away from urban centres.