In reaction to the sudden arrival of tens of thousands of refugees in the city of Hamburg (DE) in 2015, the Lord Mayor requested the CityScienceLab (CSL) at HafenCity University to facilitate a public discussion and decision-making process on locations for refugee accommodation in Hamburg neighbourhoods. With highly sensitive socio-political implications, this project demanded a well-designed technological and procedural approach. CSL employed an innovative Human-Computer Interaction tool, CityScope, to facilitate public participation and urban decision-making. A workshop process was also designed to help multiple participants and stakeholders interact effectively. Running from May to July 2016, the FindingPlaces (FP) project enabled about 400 participants to identify 160 locations accepted by Hamburg’s citizens, out of which 44 passed legal confirmation by the authorities. Overall, on a qualitative level, the project facilitated surprisingly constructive and collaborative interaction, raising awareness and a sense of ownership among participants.