Abstract
The article suggests understanding(including) better the professionalization of the formative activities and the professional activities by an approach which articulates three levels of analysis: macro (historic construction and social construction of the knowledges of the activity), méso (institutional devices (plans) of training (formation) and work) and microphone(microcomputing) (lived on the subjects, the individual dynamics). This reflection leans on the presentation (display) of various processes of professionalization stemming from empirical searches (researches) realized by the author.