The following research question serves as the starting point of this research and development project: How, in the context of a didactic design, can problem-based assignments trigger learning activities for the development of ethical and reflective competencies in students in economics courses? This paper focuses on the design of problem-based assignments as a trigger for purposeful learning activities, and, based on the literature, summarizes the principles of problem-based assignment design. A case study on the "city economics" topic outlines the implementation of these principles in a specific economics class context. In the context of a design-based research approach, the development and testing of the design are linked to the creation of design principles comprising many situations. In conclusion, the paper presents its preliminary research results.