This paper addresses context awareness of user interaction in real spaces where a number of places devoted to interaction are defined, following a concept called interaction locus (IL). In the IL a coordinated set of information notifies the user about the specific nature of the place he/she has currently entered. The interaction takes place through mobile devices which manage the context of the user, and is mediated by two agents that are called the genius loci and the numen of the user. Context awareness is achieved by cooperation between the two agents, which interact according to the user history and the place interaction opportunities. An implementation architecture is described, suited for mixed reality environments. A case study related to cultural heritage is presented.