A key feature of the identity of public law is, as Sabino Cassese has just recalled in an I*CON Guest Editorial, its traditional subdivision into constitutional and administrative law – a subdivision which the ongoing process of constitutionalisation relativises, though. Its degree varies from country to country. Moreover, two megatrends impacting European administrative legal orders, namely their Europeanisation and their alleged emancipation from the Constitution (e.g. due to the partial codification of administrative law, the emergence of the informal administrative action, the bureaucratic autonomy), constitute an antipole. Against this background, the panel aims at comparing four European national legal orders (Germany, Spain, Italy and France) in order to identify and examine the convergences and the differences in the respective administrative and constitutional dynamics; moreover, the concept of constitutionalisation itself shall be explored.