| Name | Region |
|---|---|
| Ondorse | |
| One Biosciences | |
| One Computer | Bouches-du-Rhône |
| One Logic Consulting | |
| One Opérateur | Seine-Maritime |
| One System | Ain |
| One Time | |
| One.Tel | Paris |
| One2Net | Paris |
| OneFlash | |
| Onepark | |
| Onepilot | |
| ONERA | |
| OnlineCreation.me | Gironde |
| Onlineformapro S.A. | Haute-Saône |
| OnlineOrNot S.A.S.U. | |
| Onoff app | |
| OnSpark | |
| Onxeo S.A. | |
| Onyx Informatique | Moselle |
| ooblada S.A.S. | Paris |
| Oodiva | Seine-Saint-Denis |
| Oodrive | Paris |
| Ooreka | |
| Op-Systems | Bas-Rhin |
| Op2Lysis | |
| Opale Systems | |
| Opaledata | Pas-de-Calais |
| Opalis'tic | Pas-de-Calais |
| OPALYTICA | |
| OPCoach S.A.R.L. | Haute-Garonne |
| Open | Hauts-de-Seine |
| Open Cascade S.A.S. | Yvelines |
| Open Linking | Nord |
| Open-DSI | Métropole de Lyon |
| Openaccess | Paris |
| Opencell | |
| OpenClassrooms | Paris |
| Opendatasoft | |
| Opendev | Puy-de-Dôme |
| OpenFleet | |
| Openhost | Loire-Atlantique |
| OpenIP | Hauts-de-Seine |
| OpenSpace3D | |
| OpenStudio | Puy-de-Dôme |
| Openteam | |
| OpenXtrem | Charente-Maritime |
| Opera-Fr.com | Paris |
| Ophos.com | Val-de-Marne |
| OPIA Technologies S.A.S. |