This paper studies a real-life multiple objective flowshop scheduling problem in a cardboard company which differs from the conventional flowshop scheduling problem in several aspects, such as multi-machine stations, sequence-dependent setup times, work calendars on resources, re-entrant flows, external operations, and transfer batches between stations. A simulation-based environment is presented in which the production sequence can be interactively chosen by the user or found by a tabu-search based heuristic algorithm while a discrete-event simulation deals with the timing aspect.