Passenger flow has become the new central paradigm for the design and management of high speed stations (Pitsiava-Latinopoulou M. Iordanopoulos P., 2012). The articles explains how and why railway operators conceptualize crowd versus flow concepts and produce streaming techniques that seek fluidity as well as retail value creation. To begin with, a legal-economic analysis replacing the introduction of competition into the rail system and the space pricing methods for commercial leases are provised. Then, developing the notions of flow fertilisation and commercial layout, the author explains the links between flow management techniques and retail intensification, thanks to a 2010-2017 evolution map of Paris Gare du Nord. This leads to a more generic discussion establishing the role of services in pedestrian versus consumer behaviour and micromobility patterns in main railway hubs.