Scholars have recently advocated going beyond a fetishism for one spatiality to consider a diversity of socio-spatial relations in the study of political mobilisation. The objective of this article is to propose an operationalisation of the four spatialities framework (networks, scale, place and territory) and use it in an investigation of the mobilisation for car alternatives in the Montreal city-region. The approach is to start with the spatiality and structure of the network, to identify brokers and focus on them for the detailed analysis of scale, territory and place. The article sheds light on the particular assets which the use of each spatiality, and their combination, offers for mobilisation in the city-regional context. The findings also illustrate how city-regionalism is experienced by civic actors building coalitions to defend specific causes.