How dark is the sky in France?
Sky darkness for 90 towns and parks in France, worked out from NASA satellite images of light at night (2025). 12 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Millevaches (21.87, Bortle 3), the brightest Paris (18.05, Bortle 8).
19
Bortle class, 1 pristine to 9 city center
park or dark-sky place
city
Numbers like 21.95 or 16.97 are the brightness of the sky overhead on a clear, moonless night, in mag/arcsec². The scale runs backwards: a lower number means a brighter sky, from about 22 for a natural sky to about 17 in a city center.
How the readings are made
Darkest skies in France
- MillevachesNouvelle-Aquitaine · Bortle 321.87
- the MorvanBourgogne-Franche-Comté · Bortle 321.80
- Cévennes National ParkOccitanie · Bortle 321.78
- Forêts National ParkGrand Est · Bortle 321.77
- Pyrénées National ParkOccitanie · Bortle 321.75
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.
Darkest place in each region of France
| Region | Places | Dark places Bortle 1 to 4 | Darkest place |
|---|---|---|---|
| Auvergne-Rhône-Alpes | 9 places | 3 dark | Baronnies Provençales Regional Natural Park21.61 · Bortle 4 |
| Bourgogne-Franche-Comté | 4 places | 1 dark | the Morvan21.80 · Bortle 3 |
| Brittany | 7 places | 0 dark | Saint-Brieuc20.44 · Bortle 5 |
| Centre-Val de Loire | 5 places | 0 dark | Blois20.05 · Bortle 5 |
| Corsica | 1 place | 0 dark | Ajaccio19.55 · Bortle 5 |
| Grand Est | 10 places | 1 dark | Forêts National Park21.77 · Bortle 3 |
| Hauts-de-France | 7 places | 0 dark | Saint-Quentin19.63 · Bortle 5 |
| Normandy | 4 places | 0 dark | Évreux19.64 · Bortle 5 |
| Nouvelle-Aquitaine | 9 places | 2 dark | Millevaches21.87 · Bortle 3 |
| Occitanie | 12 places | 3 dark | Cévennes National Park21.78 · Bortle 3 |
| Pays de la Loire | 7 places | 0 dark | Cholet20.33 · Bortle 5 |
| Provence-Alpes-Côte d'Azur | 13 places | 2 dark | Écrins National Park21.68 · Bortle 4 |
| Île-de-France | 2 places | 0 dark | Meaux19.27 · Bortle 6 |