Publish or Perish - do French hospitals disclose their greenhouse gas emissions for vertical differentiation?

French legislation requires large and medium-sized hospitals to publicly report their greenhouse gas (GHG) emissions. Yet, many hospitals fail to comply with this regulation, while others report voluntarily. The organizational drivers behind this behavior remain underexplored. This study examines whether hospitals disclose their GHG emissions as part of a broader strategy to differentiate themselves-similar to how they report patient satisfaction scores to signal quality. We explore whether carbon reporting is used as a vertical differentiation strategy in the French healthcare system. We used a mixed-methods approach. First, we analyzed national administrative data to test whether reporting GHG emissions is associated with reporting patient satisfaction scores. Second, we conducted semi-structured interviews with hospital managers to understand the motivations behind emissions reporting. Quantitatively, we found no significant association between the two types of reporting. Hospitals do not appear to use GHG emissions disclosure and patient satisfaction scores as part of the same signaling strategy. Qualitative findings confirmed that GHG reporting is primarily driven by internal factors such as executive leadership, process improvement, and organizational values, rather than external differentiation or patient demand. Carbon reporting in French hospitals is not currently used as a differentiation strategy. Stronger regulatory enforcement is needed to ensure compliance. In addition, hospitals require support-through methodological guidance, training, and the development of dedicated sustainability roles-to integrate environmental performance into their management systems and contribute meaningfully to healthcare decarbonization.