Résumé : This paper estimates the impact of workforce diversity on productivity, wages, and productivity–wage gaps in a sample of French firms using data from a comprehensive establishment-level survey (REPONSE) for 2011 matched with companies’ balance sheet data. Controlling for a wide set of workers’ and firms’ characteristics, findings suggest that age and gender diversity are negatively linked to firm’s productivity and wages while education diversity is positively linked. Contrary to some widespread beliefs, the paper finds no differential effect according to manager characteristics (gender, age, education and tenure) but some heterogeneity according to the type of proprietary structures of the firms.