| Code | Name | Region |
|---|---|---|
| FROE4 | Orbec-en-auge | 14 |
| FROBY | Orbey | 68 |
| FRC7Y | Orcay | 41 |
| FREER | Orcet | |
| FR7YT | Orchaise | 41 |
| FROHP | Orchamps | 39 |
| FROV2 | Orchamps-vennes | 25 |
| FROVT | Olivet | 45 |
| FR2VL | Olizy-et-violaine | 51 |
| FROLA | Ollainville | 91 |
| FRO83 | Ollieres | 83 |
| FROGU | Olliergues | 63 |
| FROOL | Ollioules | 83 |
| FROM2 | Olmeto | 2A |
| FROSM | Olonne-sur-mer | 85 |
| FR43H | Olonzac | 34 |
| FROLO | Oloron-sainte-marie | 64 |
| FROMZ | Omet | 33 |
| FROJM | Omey | 51 |
| FROYC | Oncy-sur-ecole | 91 |
| FRJFM | Ondes | 31 |
| FROD5 | Ondres | 40 |
| FROLC | Onet-le-chateau | 12 |
| FRAOJ | Onjon | 10 |
| FRLY6 | Onlay | 58 |
| FRONG | Onnaing | 59 |
| FRO3N | Onnion | 74 |
| FROFV | Offranville | 76 |
| FROJG | Oger | 51 |
| FROLB | Ogeu-les-bains | 64 |
| FROHR | Ohain | 59 |
| FROGI | Oignies | 62 |
| FROYI | Oigny-en-valois | 2 |
| FRGTO | Oingt | 69 |
| FRIOR | Oiron | 79 |
| FROIR | Oiry | 51 |
| FROSY | Oisly | 41 |
| FROS4 | Oisseau | 53 |
| FRO3T | Oisseau-le-petit | 72 |
| FROIL | Oissel | 76 |
| FRRGX | Olargues | 34 |
| FROLY | Olby | 63 |
| FRYZX | Olemps | 12 |
| FR2KL | Oeuf-en-ternois | 62 |
| FROJY | Oeuilly | 51 |
| FROFD | Offendorf | 67 |
| FRE4R | Offin | 62 |
| FRZBC | Nyons | 26 |
| FROHB | Oberhausbergen | 67 |
| FROB2 | Oberhergheim | 68 |