Résumé : The breakdown of relations between citizens and the ruling classes is leading to a problem of trust in the state and its officials. Ethics and transparency are therefore tools that serve as a moral pledge to restore trust in institutions and create healthy conditions for the relationship between public officials and citizens. In Brussels, the institutional complexity combined with judicial cases complicates the success of bills introducing more ethics and transparency. In this respect, this study analyses the determinants of the adoption of measures. During the 2014-2019 (6th) legislature, it appears that public opinion acted as a catalyst and accelerator for decision-making. On the contrary, the local-regional structure and the divergence of interests between communities slowed down the process of adoption of strong measures.