Moving as a French or Dutch citizen to Belgium should be easy, given the freedom of movement of EU citizens. Reality paints a different picture, however. This paper analyses the practices of Belgian municipalities and the Immigration Office as to the registration of EU workers, self-employed, jobseekers and their family members. It is based on a desk study, a survey among a sample of municipalities as well as semi-structured interviews with municipal officials, the Immigration Office and other stakeholders. The paper adopts a legal understanding of 'procedural justice', focusing on dimensions of equal treatment and transparency. It shows that the achievement of procedural justice for EU citizens is impaired by divergent and at times questionable practices by street-level bureaucrats. These practices indicate, among others, that varying levels of 'deservingness' of residence in Belgium can be observed within the category of mobile EU workers. Furthermore, increased digitalization and the use of intermediaries in the registration procedure facilitate and reinforce differential treatments among EU citizens and their family members.