Before revision: Based on a simple analysis of the reports of Sant\'e Public France , we show that the real incidence during the second wave of the Covid-19 outbreak is around 60\% of the mean positivity of virological tests realized week after week in France. The fraction of the French population infected at the beginning of September is about 3\% (2 million people ).
After revision: Based on a simple analysis of the reports of Sant\'e Public France , we show that the real incidence during the second wave of the incidence at the beginning of August was about 0.8\% and rose to about 2.4\% of the total population at the beginning of September is about 3\% (2 million people ).