A growing number of city governments worldwide engage in sustainability reporting, voluntarily and responding to legal pressures. Diverse practices emerged based on unique choices concerning formats, periodicity, authorship and dissemination efforts. Such design questions and associated outcomes are highly relevant for practitioners yet unaddressed in standard guidelines and most prior research that primarily concern content and conjectured reporting benefits. This article presents a framework suited to assessing real-life practices and outcomes. An exploratory evaluation in Amsterdam, Basel, Dublin, Freiburg, Nuremberg and Zurich suggests that sustainability reporting can benefit organizational change, management and communication yet also lead to 'fatigue' and discontinuation.