The introduction of didactic devices such as investigation workshops at university level reveals some difficulties related to missing professional praxeologies. Indeed, the paradigm of the visit of works is dominant in those institutions where a ‘pedagogy of teachers' is widespread: investigation workshops require the mastery of a ‘pedagogy of investigation', which is based on different professional praxeologies. The aim of this work is to present a didactic analysis of the exploration of a professional type of tasks related to the design of generating questions for such a workshop. We chiefly underline the parts played by the encounter with difficulties of the profession and the processes of dissemination of praxeologies: these two types of situations prove to be catalysers of the construction of praxeologies, in particular in the elaboration of the logos of professional praxeologies.