In the past decades, research and practice focused a lot of attention towards traceability in the context of software requirements, food supply chains, manufacturing, and aviation industry. As legislation and regulations in software systems become increasingly relevant, traceability of legal requirements is of great importance. In this study, we aimed to create a framework in which the basis for traceability of legal requirements is addressed. To be able to do so we conducted five case studies at five Dutch governmental institutions, which was followed by a three-round focus group. The resulting framework comprises 22 (layered) traceability elements in relation to three domains that offers a reference model to determine how traceability can be applied in software system design, in the context of the Dutch government.