This article sets out to identify key competencies which language tutors need to develop in order to manage synchronous online teaching. In order to aptly monitor interactions with distant learners, it is proposed that three types of regulation pertaining to socio-affective, pedagogical and multimedia aspects are required. On the one hand, this research aims at specifying these competencies and, on the other hand, it seeks to identify the relevance of reflective analysis for professional development. The context of this study is a teacher training programme for Masters Degree students in teaching French as a foreign language that provides trainees with the opportunity of teaching online to intermediate-level students of French from a North American university via a desktop videoconferencing platform. This programme first endeavours to put trainees in a professional situation by getting them to prepare and administer sessions in order to confront them with the specific challenges of synchronous online tutoring. Second, it seeks to help them to gain insight into their own activity by developing critical thinking towards their own practice. The data elicited for this research derive from the tutor trainees' interpretations of their own practice when confronted with the film of their own situated activity. The episodes chosen by the trainees to feed the self-confrontation process constitute significant units because by being told and commented upon, they elucidate how and to what extent competencies are built. Three discursive strategies have been identified and used to organise the content analysis of the data: description; expression of a difficulty; reflective review of the activity. The strategies used by trainees to verbalise their own activity can inform teacher educators about the constraints of the work situation and about the resources trainees need to deploy to face up to this unknown professional situation. Results indicate that trainees concentrate particularly on pedagogical aspects that distance and faulty technology have rendered complex. The encountered difficulties are equally distributed between a repertoire of competencies pertaining to language teaching and competencies more directly linked with online teaching. Finally, this study has enabled us to assess the potential of self-confrontation for teacher practice and leads us to propose directions for improving this training device.