Data fusion is the final step of a typical data integration process, after schematic conflicts have been overcome and after duplicates have been correctly identified. We present the relational data fusion system FuSem, which uses schema mappings and information about duplicates to decide what to fuse, i.e., which tuples to merge into one. The aspect emphasized by the demo is how to fuse the duplicates with FuSem. First, it offers several conflict resolution functions to handle data conflicts among duplicates. Furthermore, different fusion semantics proposed in the literature, such as MatchJoin or ConQuer, can be compared and visually explored. Optimized execution allows interactive access to the data and thus to explore the different data fusion procedures.