This contribution deals with the views of in-service school teachers about a good lesson during a four-week period of teaching practice for future teachers as part of their bachelor’s degree and explains the correlation between the teaching practice and the didactics of German as a foreign language and foreign languages didactics in general. After describing the organization of the teaching practice and the theoretical background of the teacher training courses at the university, the contribution goes on to investigate and discuss what the student teachers put into practice in their lesson planning. It emerges that the interviews with the teachers’ mentors about a good language lesson contain both pedagogical as well as didactic themes and that the professionalization of student teachers can differ depending on the in- service teacher.