Common ragweed (Ambrosia artemisiifolia L.) has been detected in France in the middle of the XIXth century. It has spread throughout the territory during the XXth century with a critical evolution. Public policies have not been able to contain this spread at the moment, and it is now difficult to find ways to tackle the invasion. Publication of national and regional maps seems to be an effective tool to draw up an overview of the situation and build management strategies. With a set of historical and modern data collected all over the French territory, and from many different stakeholders, we consider the progress of the species in time. The system of legislation applied locally is analyzed with regard to the data of presence of the species. Several examples of maps are proposed, which aim at determining thresholds of intervention. The reliability of the results is analyzed in the light of the pressure of sampling.