The purpose of this presentation is to describe how professional knowledge is co-constructed between a teacher-trainer (tutor or mentor) and a student-teacher. In this exploratory study, the Lesson Study approach is transposed to interactions between tutors and their trainees during their interviews. This particular approach of an LS is called the "Mentoring Conversation Study" (MCS) (De Simone, 2019). Seven tutors at pre-school level and seven secondary school teacher-trainers from the french-speaking Switzerland are involved in this study. This approach shows among others the knowledge that teacher trainers mobilize during interviews to guide the student-teachers. The questions that guide this study are :
- What are the contents mobilized in the tutors' speeches ?
- From a longitudinal perspective, what effects does the MCS system have on teacher trainers ?

Democritus University of Thrace