The aim of this article is to analyse how the conceptual and survey tools of geography can be used to perform urban nostalgias in the artistic domain. Starting with the concept of the tomason, an urban object that has lost its function but persists in the urban landscape, the text describes a geographical-theatrical research project to collect tomasons in the Saint-Gevais district in Geneva and transpose them to a theatre for subsequent performance. During a month-long immersion in this district, a theatre director, a sound designer, a geographer, and two actors went in search of tomasons, equipped with the tools of the social sciences (interviews, direct observations, participant observation and reflexivity) and the tools employed in directing actors in a theatre. The retrospective analysis of the survey in May 2021 explores the reciprocal effects of the use of tomasons for both the scientific and artistic fields: what is the impact of this dialogue between geography and theatre for survey practices around the spatial dimension of memory, and how does the production of a geographicaltheatrical performance influence the practice of acting and narrative assemblage?