Supervision is a central practice in the training of psychiatric therapists. This research is based on the qualitative analysis of empirical data consisting of 28 hours of video recordings, 8 hours of which are transcribed in full. This doctoral research aims at identifying the interactional resources mobilized in supervision when supervisors and therapists talk about the therapeutic relationship they have with patients. Analyses reveal that participants display their emotions in a multimodal way and orient towards a collaborative management of affectivity. The interactional processes of involvement and affiliation lead to the therapist's self-reflection concerning his affective and relational stance with the patient. In the context of face-to-face supervision, interactions are constantly (re) configured according to deontic, epistemic and emotional orders, revealing the complex interface of power, expertise and affectivity. Supervisor's professional competences lie in the fine-grained and collaborative management of relationships with therapists and in the co-construction of affective and cognitive trajectories during supervision encounters. These mechanisms may contribute to therapist's learning processes.