Many studies have been written about the turbulent and, above all, interesting legal past of the city of Rijeka. And while Italian historiography pays particular attention to the legal issues arising from the occupation of the city by D'Annunzio, Croatian legal scholars deal with this historical phenomenon quite sporadically. In order to contribute to the analysis of the legal substrate of Danunziada and to stimulate discussion, the authors explain the socio-political context of the occupation and why the newly created circumstances constituted a violation of the international law of war with regard to the occupation. History has shown that in times of great unrest and sociological, economic, cultural, political, and other disturbances, there is an increased danger of the instrumentalization of criminal law for political purposes. To examine whether criminal law was used outside of its doctrinally proclaimed purposes, and for the aims of the occupying power, research was conducted using the special archival fund of the State Archives in Rijeka. The sample consisted of 16 files of the City Court of Rijeka, which were opened from September 12, 1919, when D'Annunzio entered Rijeka, until June 4, 1920, when the Trianon Peace Treaty was concluded, aiming to provide a final solution to the “Rijeka issue.” Although the results of the analysis confirm the thesis that the instrumentalization of criminal law occurred on a normative level by erasing the existing Hungarian law and installing the “new Italianized Rijeka law,” in adjudication, this newly created law was used to preserve the independent and impartial work of judges and to promote justice in addressing the individual circumstances of defendants.