The work reported here takes place in the educational domain. Learning with Computer-Based Learning Environments changes habits, especially for teachers. In this paper, we wish to demonstrate through examples how learning sessions set up in a Game-Based Learning environment may be regulated by the teacher thanks to observation facilities. Providing teachers with feedback (via observation) on the ongoing activity is thus central to being aware of what is happening in the classroom, in order to react in an appropriate way and to adapt a given pedagogical scenario. The first part deals with the observation of a learning environment, based on traces left by users in their collaborative activities. The information existing in these traces is rich but the quantity of traces is huge and very often incomplete. Furthermore, the information is not always at the right level of abstraction. That is why we explain the observation process, the assets of a multisource approach and the need for visualization linked to the traces. The second part of the paper focuses on our view of learning games illustrated through the "pedagogical dungeon," a game-based environment that we have developed. In the third part, we illustrate these concepts in the pedagogical dungeon equipped for observation and with the capacity for collaboration in certain activities. Finally, the feedback about the experiments presented is discussed at the end of the paper. (Contains 1 table and 12 figures.)