English: Known historical seismicity from macroseismic data. (a) Seismicity map centered on metropolitan France (SISFRANCE database, 2017 release). Earthquakes are plotted according to five distinct epicentral intensity classes. Regions mentioned throughout the text are reported in the caption; (b) temporal plot of the seismicity, including the 5743 events of the EPCSIRENE table, from year 463 to year 2007. The number of events for each intensity level is presented on the right. Undefined epicentral intensities (UEI) are arbitrarily plotted along the Io = I axis. Note that the event showing an epicentral intensity value of X–XI is the 1755 Lisbon earthquake, not reported in (a).