| Cabinet Faure Informatique | Loire |
| Câblage Connectique Européen | Territoire de Belfort |
| Cablego S.a.r.l. | Meurthe-et-Moselle |
| Câblerie Daumesnil | |
| CACD2 | |
| CACEIS | |
| CAD Interop | Paris |
| CAD'indus | Haut-Rhin |
| Cadcams | Val-de-Marne |
| CadCao | Isère |
| Cadlink | Gironde |
| Cadlog S.A.S. | Alpes-Maritimes |
| Caduciel Informatique | Haute-Saône |
| CADvision | Paris |
| Caen Informatique | Calvados |
| CAFCA | Yvelines |
| Cailabs | |
| Caisse d'Épargne | |
| Cajoo Technology | |
| Cakemail | |
| Calcul Quantique Université de Montpellier | |
| Caldera | Bas-Rhin |
| Calixar | |
| Callbell | |
| Calldesk | |
| Calliope Business Solutions | Seine-Saint-Denis |
| Callisto | Haute-Garonne |
| Calliweb | Hauts-de-Seine |
| Caloga S.A.S. | Paris |
| Camarin | Hauts-de-Seine |
| Campus Région du numérique | |
| Canal Internet | Paris |
| Canal-Cable | Hauts-de-Seine |
| Canon Bretagne | Ille-et-Vilaine |
| Canon France | Hauts-de-Seine |
| CANOP | |
| Canopée | Bouches-du-Rhône |
| Canyon Technologies | Bouches-du-Rhône |
| Caocao | |
| Cap Digital | Paris |
| Cap Horn VC | |
| CAP Informatique | Marne |
| Cap On Line | Ain |
| Cap Telecom | Bouches-du-Rhône |
| Cap Visibilité | Essonne |
| Capa Electronic | Loire-Atlantique |
| Capagro | |
| Capcir | Haute-Garonne |
| CapData | Hauts-de-Seine |
| Capensis | Nord |