Cities today are confronted with ever-greater social diversity, yet urban planning struggles to engage with differences. This thesis investigates, under the frame of the DiffUrb project, how urban difference is actively produced through everyday spatial practices, focusing on former Yugoslavs in four European cities (Geneva, Brussels, Turin, Hamburg). Using a qualitative methodology centered on narrative interviews with mental mapping, the research uncovers the subtle ways this migrant group inscribes itself in the city. Rather than forming visible ethnic enclaves, their presence emerges in selective moments of visibility. Through comparative analysis, the study reveals that a group's spatial (in)visibility can be both a result of city policies and a deliberate strategy of belonging, and this situated multiplicity is mapped through a composite narrative map. Drawing on critical urban theory, the thesis argues that difference should be understood as a dynamic, negotiated process rather than a fixed trait. Finally, the proposal of this work is a framework entitled Situated Multiplicity Planning: an approach to urban planning that listens to unheard narratives, embraces the multiplicity of urban experiences, and remains adaptive in the face of urban uncertainty. By illuminating the spatial silence of a diaspora and its interplay with urban structures, the research offers a nuanced understanding of inclusion in the city and a call to reimagine planning as a collaborative, iterative practice attuned to complexity.