Abstract
Aware of a crisis situation (housing, facilities, population growth), the Seine Prefecture decided in the late 1950s to carry out a major project to process the 1954 census and produce a series of statistical and cartographic data to aggregate all the census data at block level. This global vision, bringing together information on occupational classes, housing conditions and building types, was intended to serve the major planning and development projects of the metropolis. For the historian, these documents represent an incredible source of information on the situation of the Paris metropolitan area in 1954. This research paper looks at the conditions under which the 1954 census was produced, and how it was transformed into a database. The aim was to create a Geographic Information System, enabling statistical and cartographic processing, in order to open up new avenues of research into the social and urban history of the Parisian metropolis.