I will present some results from my doctoral work which concerns the study of the conditions and constraints determining teaching practices when imple- menting mathematics’ study and research paths in French secondary schools during the 2013–2015 period (Bernad 2017). In the framework of this inquiry, I highlight elements of a teacher’s praxeological equipment that are useful for the achievement of the project to implement such a study and research path (SRP). I will focus on under- lining how the study of didactic praxeologies activated by a teacher has led me to make the hypothesis that he achieves to extract the collective class from the paradigm of visiting works in order to fall within a paradigm of study through research. It will also show these analyses have led me to think that the praxologies’ model and the individual-collective dialectics, media-milieu dialectics, questions-answers dialec- tics are relevant tools for thinking about the teacher’s role, and the anticipation of his decisions in the setting up of closed SRP.