| ACKSYS Communications & Systems | Yvelines |
| ACM2E | Paris |
| ACMD | Loire-Atlantique |
| ACMI | Paris |
| ACMR Informatique | Nord |
| ACN Communications France S.A.S. | Hauts-de-Seine |
| Acofase | Savoie |
| Acquisys | Yvelines |
| Acquitek | Essonne |
| Acreat | Paris |
| ACRI-ST | |
| Acrona | Bas-Rhin |
| AcroPDF Systems | Hauts-de-Seine |
| ACS Biotech | |
| Acs2i | Paris |
| ACSIEL Alliance Électronique | |
| Acsinfo | Maine-et-Loire |
| ACSO | Yvelines |
| Acssiom | Vosges |
| Act 21 | Haute-Garonne |
| Acta Digital Services | |
| Actemium France | |
| Acteos S.A. | Nord |
| ACTH | |
| ACTI | Paris |
| ACTIA Group | |
| Actibase | Métropole de Lyon |
| ACTIC | Meurthe-et-Moselle |
| Acticoncept | Seine-et-Marne |
| Acticor Biotech S.A. | |
| Actideo Informatique | Drôme |
| Actif Azur | Alpes-Maritimes |
| Actif Grand Ouest | Loire-Atlantique |
| ACTIF systèmes | Loire-Atlantique |
| Actigraph | Calvados |
| Actilis | Morbihan |
| Actility | Paris |
| Actiloc | Bouches-du-Rhône |
| Actimac Solutions Pro | Calvados |
| Actimage | Paris |
| ActiNetwork | Bas-Rhin |
| ACTIO.fr | Essonne |
| Action Micro | Ariège |
| Action-Web S.A.S. | Hauts-de-Seine |
| Actioncom | Loire |
| Actirone | Paris |
| Actium SI | Côtes-d'Armor |
| Activ'IT | |
| Activ-Sites | Bouches-du-Rhône |
| Active Asset Allocation | |