In 2015, during my last year of legal studies in town planning and environment at the University of Lille, I worked for the European Council of Town Planners. Thanks to this work, I discovered the rich diversity of European legal systems in town planning and environment, and the multiple ways in which different European legislations and separate legal fields influence each other. The fascination derived from this research, led me, step by step, to pursue a PhD on the complex relation between oil flows, and the legal framework that emerges in response to and in preparation for oil-related spaces and environments. I argue that a thorough understanding of this intricate relationship is a necessary foundation for meaningful post-oil planning and careful assessment of the issue of future oil heritage sites. The case studies selected for the research - mainly Dunkirk in France - exemplify the important role that port cities, as key nodes in the system of oil flows and petroleum refining, have played in both oil-related spatial and legal development.