This article investigates the effects of union and nonunion employee representation (ER) on the use of high-performance work systems (HPWSs) in the French context. We use microdata from a nationally representative survey (REPONSE 2010–11) and estimate models dealing with the potential endogeneity of ER. After controlling for endogeneity and for a range of workplace characteristics, regression analyses suggest that neither union nor nonunion representatives are inherently against the use of HPWSs. Moreover, these forms of ER cannot be regarded as substitutes for one another. Results vary, depending on what type of bundle of practices is considered.