Implementing sustainable development is a challenge that all European cities are facing today. In recent years a growing number of tools, manuals and initiatives have been developed in order to support cities in this endeavour. However, the implementation of this knowledge remains far from satisfactory and even the most popular tools are finding it difficult to reach a wide audience at the local level. The PRIMUS project addressed this need to bridge the gap between research and local policy-making. Based on an explorative application of two research-based sustainability management tools which involved more than 50 European cities, as well as on the discussions held as part of the Informed Cities Initiative, in this chapter we discuss the conditions of effective knowledge brokerage between local policy-makers and researchers working on urban sustainability.