20 cities
| City | 2025 Pop. ↓ |
|---|---|
| Orleans | 116,685 |
| Orange | 30,530 |
| Oyonnax | 25,697 |
| Oullins | 25,592 |
| Orvault | 25,338 |
| Olivet | 22,604 |
| Ozoir-la-Ferriere | 22,530 |
| Orly | 20,528 |
| Orsay | 17,817 |
| Octeville | 16,951 |
| Osny | 16,545 |
| Outreau | 15,648 |
| Ollioules | 13,916 |
| Oloron-Sainte-Marie | 12,611 |
| Obernai | 12,138 |
| Orthez | 11,857 |
| Oissel | 11,495 |
| Ostwald | 11,261 |
| Olonne-sur-Mer | 11,157 |
| Oignies | 10,609 |