Covid-19 pandemic have recently raised lots of issues about the way we lived socially and have ledto various studies for our social behaviour to be adapted to struggle the crisis. This report presentsthe work done during the master thesis regarding this virus contamination. The goal of this thesiswas to understand and evaluate the infection risk under different ventilation conditions, betweena standing and infected person, and a sitting one. Therefore, a CFD study has been performed inparallel with another thesis containing relevant experiment data. To achieve a model coherent withthis data, we use a whole process: literature review to collect data and get used to CFD problemsin indoor environment, simplified geometry and mesh to understand the available CFD models,mesh study to perform efficient and accurate calculations, additional experiments to improve themodel, After validating the model with experimental data, we can observe the virus concentrationin the room and deduce which configuration is the best to limit contamination. CFD study showsthe experiments realized hide some critical points where the risk of infection is the highest duringthe exhalation of the infected person.