The ultimate aim of this project is to provide simulations of the risk of nosocomial spread of SARS-Cov2 in French hospitals as quickly as possible (within a few weeks). We will use investigation method, analysis and simulation tools derived from research works carried out in the field of multidrug resistant bacteria (MDRB) and Influenza. This project is the result of the working group “Modeling the nosocomial dissemination of Covid-19”, set up two weeks ago to which several French teams in the field have responded proactively whose other projects are submitted to this call for tender. We propose here (i) to make available the contact data collected in the framework of the i-Bird program and the SocioPattern consortium, (ii) to carry out very quickly investigations of dynamic human contact structures in a sample of hospital clinical ward types in order to make these data available for agent based simulation tools already developed, (iii) to implement extractions and gather data from health data warehouses of hospital-university sites from 1 January 2020 until the end of the epidemic. This should make it possible in the coming weeks to provide the most accurate possible results on the risk of nosocomial spread of SARS-Cov2 and, above all, to contribute to optimizing healthcare organization policies with regard to the risk of SARS-Cov2 acquisition in hospitals, for patients and health care workers, and its consequences.