Microsimulation methods have become an important tool to support evidence-based policies. Within the research of the MikroSim project, the aim is to generate a synthetic, but realistic dataset based on the full population of Germany. In order to produce a fully geo-coded dataset, where information is generally available on aggregate levels of different hierarchies, micro units (households and persons) have to be placed into geo-coded dwellings. The microsimulation model involves mathematical optimization problems with integrality constraints on some or all of the optimization variables. It is therefore very natural to employ combinatorial optimization techniques to handle these discrete structures efficiently.