Nowadays, there is no tool that provides a global, permanent and “real time” view of road freight transport flows. However, this type of mapping is already available for air and sea traffic and could be useful to transport companies, e.g., setting up logistics hubs in strategic locations, and to public authorities, e.g., quickly knowing the impact of regulations, the contribution to congestion, or the impact of emissions. This kind of tool could obviously make information about road freight traffic more accessible, and allow for the consolidation of flows at both the interurban and urban levels to help decarbonize freight transport and logistics. The main contribution of this paper aims to provide a design sketch of an observatory of road freight transport flows based on signalling data from mobile network, which is accurate enough for that type of study and which does not require any supplementary installation of application on mobile devices. This kind of observatory is therefore related to the concept of Physical Internet through its objectives. This observatory will have to ensure privacy and business confidentiality by respecting the constraints set by the General Data Protection Regulation (GDPR) and the ePrivacy directive, i.e., a short-term anonymization in the French case. Thus, the second contribution of this paper is a literature review on the methods that could be useful to solve these questions.