Two criteria have been added to the Common Agricultural Policy (CAP) in order to foster biodiversity: the cross-compliance rules and the green direct payments. This research discusses the capacity of these criteria to transform farmers’ cognitive attitude towards the protection of biodiversity. It is based on multiple interviews with CAP beneficiaries and local actors involved in the CAP implementation, in France and Spain. It shows that the neo-liberal instruments chosen for the implementation of the cross-compliance rules and the green direct payments have a limited capacity to produce positive cognitive effects on beneficiaries. Two complementary factors explain these limited effects: the content of the instruments, and the type of bureaucratic encounters they create. One eventually observes a dual process of socialization: biodiversity instruments socialize farmers to neo-liberal governance as much as they socialize them to biodiversity protection.