In this talk, we show how modelling appears as a federating transversal theme for mathematics and sciences in Geneva Lower secondary education. We then present a course for in-service teachers, within European project PRIMAS. Based on broad definition of modelling, we introduce a typology in three levels of modelling activities that we exemplify to classify and analyse a few activities in relation with modelling in the new mathematics textbook for grade 7 for all French speaking Switzerland.