The emergence of various informal governance spaces reaching beyond the borders of administrative units and statutory planning is an increasingly important feature of the development of cities and regions in Germany. Social and economic processes take place at ever more diverse and diffuse spatial scales and their effects on spatial development are becoming ever more complex to comprehend. In response to this increase in the complexity of socio-spatial relations, new governance structures have been experimented with in increasing numbers, producing a rich patterning of both formal, statutory hard spaces, and soft spaces – here referring to new, non-statutory or informal planning spaces which overlap, intersect and complement each other at various moments in time and place (see also Reimer, 2012, Harrison and Growe, 2014). An improved critical understanding of the emergence, practices, evolution, impact and democratic legitimacy of soft spaces therefore seems a prerequisite for a more balanced and effective spatial and regional development.