In this paper, we present the impact of user interaction in the recognition of off-line structured documents. This interaction requires solving two major problems: how interpretation results will be presented to the user, and how the user will interact with analysis process. We propose to study the effects of those two aspects in the context of an interactive method (IMISketch) for off-line handwritten 2D architectural floor plan recognition. The use tests are realized in collaboration with researchers in cognitive psychology (more than 100 persons participated in the tests). The experiments demonstrate that (i) a progressive presentation of the analysis results, (ii) user interventions during it and (iii) the user solicitation by the analysis process are an efficient strategy for interactive recognition of offline documents.