The HRM obligations to respect diversity and to act without discrimination modify the psychological contract of employees and create new related beliefs about how work should be done. Our qualitative research carried out in a temporary work company in France offers a better understanding of beliefs limiting or favoring the integration of the diversity, and the way in which they are maintained. Despite the evolution of beliefs, our results point to a mismatch between convictions for inclusive management of diversity and some dissonant practices imposed by clients.