| City | 2026 Pop. ↓ |
|---|---|
| Orleans | 116,392 |
| Oullins-Pierre-Benite | 38,932 |
| Orange | 30,249 |
| Orvault | 29,601 |
| Orly | 24,985 |
| Olivet | 24,303 |
| Oyonnax | 22,522 |
| Ozoir-la-Ferriere | 21,819 |
| Osny | 18,218 |
| Oree d'Anjou | 17,690 |
| Orsay | 17,141 |
| Ollioules | 15,049 |
| Ostwald | 14,826 |
| Obernai | 13,329 |
| Outreau | 12,968 |
| Oissel | 12,431 |
| Onet-le-Chateau | 12,378 |
| Ormesson-sur-Marne | 11,281 |
| Orthez | 11,187 |
| Oloron-Sainte-Marie | 10,721 |
| Oignies | 10,616 |