Starting from a case study on the implementation of the Bus Attitude, a service project within RATP, the purpose of which is to establish a genuine service relationship onboard Paris buses, we attempt to question the operational implementation challenges encountered by management, especially as for the human ressources ones, even though the project seemed to have been prepared adequately. We propose referring to the Abbott conceptual framework to account for these challenges which seem to reflect more than just a “reluctance to change”. The conceptual framework, which emphasises the systematic observation of how so-called professional groups address an issue according to a certain understanding, allows outlining a certain number of shortcom...