This polygon shapefile contains the boundaries of urban blocks in Paris during 1553. These data were taken form the Basel plan and characterize urban desity levels for each block according to the representation on the plan (low, medium, high). The Plan of Truschet and Hoyau (called the Basel Plan), shows the city around 1552-1553. The ALPAGE programme aims to provide collaborative tools for the Humanities and Social Sciences and for Information Communication Technology (ICT) allowing for the development of research about the Parisian urban area. This aim is achieved by means of a GIS that includes cadastral and historical layers. This data is a direct result of the work of the researchers from the ALPAGE consortium who released this data under an Open Data Commons Open Database Licence (ODbL). Therefore, use of this data by others must respect the legal requirements specific to this licence. All freely downloadable data contains the shapefiles, metadata file and licence files describing the users rights and responsibilities. All data produced within the consortium is published in this way with the exception of any ongoing work which is in process of academic evaluation (masters, doctoral thesis, habilitation to supervise research). This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.