This paper analyses how French general practitioners? (GPs) labour supply would respond to changes in their fee per consultation, seeking to determine whether there is a backward-bending curve.?Because French GPs? fees only evolve very slowly and are generally fixed by the National Health Insurance Fund, fee variability is not sufficient to observe changes in labour supply.?Therefore, we designed a contingent valuation survey randomly presenting GPs with three hypothetical fee increases.?Empirical evidence from 1,400 GPs supports the hypothesis of a negative slope in their labour supply curve.?This suggests that increasing fees is not an effective policy to increase the supply of medical services. JEL Codes: C21, I12, J22, J4.