Defining polycentric urban areas through commuting cohesion. Through commuting cohesion in France

International audience; Though the visualization of the daily commuting patterns around French urban area, we identify subcentres of commuting activities, illustrating the emergence of new urban polycentric structures. Via computed metrics on these graphs and an associated diachronic approach on the census data for the years between 1975 and 1999, we analyze the topological structure of the graph series. This analysis demonstrates the combined small world and star topology present in the data.