Milky Way Planner has pages for 6 dark sky places in France: 5 reserves and 1 tourism destination. Their Bortle classes run from 2 to 6. Each page has the Bortle class, the best months for the Milky Way and a free visibility calendar.
Reserve · Bortle 2
Reserve · Bortle 4
Reserve · Bortle 6
Reserve · Bortle 2
Tourism destination · Bortle 4
Reserve · Bortle 4