“Shrinking Cities”, appeared in American literature (Weaver, 1971) refers to a phenomenon of “urban shrinkage”, however it may seem misleading because, in many cases, the cities supposed to shrink do not lose area. On the contrary, very often, urban agglomerations continue to spread their mark on the territory. The shrinking city reflects the phenomenon of urban decline.
Depending on the cases and researches, demographic (loss of population), economic (economic changes, loss of activities, functions and jobs) and social (development of unemployment and insecurity) indicators are put forward to explain or give a definition of the shrinking city. The link between these different dimensions is not yet explicitly stated. However, it seems essential to take into account the “additional” nature of the causes leading to the phenomenon as well as its consequences in cascade, in particular spatially and morphologically.
These declining cities are often cities that fail to gain influence in our connected and hyper-spatial organization. They are ill-equipped to compete with the big cities in the fields of research, education and skilled employment, and they become dependent upon them. Sometimes poorly served by transport networks and located far from information and communication networks, these small and medium-sized cities suffer from their spatiality and their lack of infrastructure.
The origin of the phenomenon of decline differs from country to another. For example, in American urban history, the economic dimension of decline through deindustrialization is often emphasized. These economic upheavals have an impact on the number of jobs. Still in the American case, deindustrialization has had demographic effects with the departure of populations to the suburbs, these residential neighborhoods located outside the cities. Population decline is therefore linked to economic decline. This population movement, called suburbanization, triggered social problems, such as the impoverishment of the centers and an accentuation of the processes of socio-spatial segregation. We therefore understand from this example that a study angle can be dominant or initiator, but it has the effect of generating the others.

WORLDWIDE
In Europe, entire regions have seen their fates sometimes brutally sealed by this process of decline, such as the North of Great Britain or the Ruhr region in Germany. The phenomenon has heavily impacted the former European industrial regions, mining towns and those of the steel and textile industry.
This urban manifestation is gaining momentum around the world. Until the 1970s, this phenomenon of decline was largely linked to developed countries (around 70% of shrinking cities), particularly affecting the United Kingdom, Germany and the United States. However, we have noticed, in recent years, that the developing countries are not spared.
Faced with the scale of the phenomenon, our way of organizing cities and their interactions can be called into question. The globalized economy has catalyzed the phenomenon of decline by marginalizing cities that cannot find their place in this international economic competitiveness. Conversely, other cities acquire a power of global influence by concentrating the activities, command and control functions, institutions and services, synonymous with urban growth.