Parking consumes large amounts of urban space and plays a central role in sustaining car dependence, yet municipal efforts to reform parking policy face significant barriers. In Germany, one challenge is that municipal autonomy is constrained by the legal framework set at the state and federal level. This thesis examines how the legal framework affects the action space of municipalities in the German state of Baden-Württemberg regarding on-street parking reform. Previous research has become outdated due to a number of recent legislative reforms and has not sufficiently examined the way municipalities perceive and react to the legal framework. To address this gap, the study combines two elements: First, a legal analysis of available parking reform instruments, using multi-level governance as the theoretical framework. Second, it presents a comparative case study of two municipalities, Freiburg and Stuttgart, based on semi-structured interviews with municipal staff and document analysis, drawing on a theory of action space. The findings show that the municipal action space is restricted not only by formal legal restrictions on which parking policy instruments can be used and how they can be applied, but also further constrained by legal ambiguities and administrative requirements that strain limited staff and financial resources. As a result, municipalities are hesitant to innovate despite recent reforms that expanded formal options. Beyond confirming earlier calls for legal reform, the research identifies operational challenges as another area requiring change and provides an updated overview of relevant legislation.