ObjectiveFollowing the evolution of public health policies, which are increasingly experienced by workers in this field as a lack of interest from the supervisory authorities, the aim was to clarify the missions of the medical-psychological centers (CMP) for children and adolescents and above all to testify, for the benefit of colleagues and partners, to the creativity of these structures, to which users are flocking. MethodA study day on the specificities of sector work in child psychiatry was held at the Ste-Anne Hospital in Paris in June 2019. ResultsAs a participant in the first round table entitled “From the land to the territory”, I will take up here what I tried to make more visible regarding professional practice in CMPs, based on the implementation of associated knowledge, at a time when public health policies are situated at the territorial level. DiscussionI set out how and where the child psychiatrist intervenes in the CMP. It depends on both his own knowledge and what is expected. ConclusionThis epistemological thinking could help the child psychiatrist to communicate directly with the people he serves.