His areas of interest include cities and migration, border regimes, urban citizenship, urban social movements and participatory politics. Before coming to Humboldt University, he taught at Freie Universität Berlin, at the San Francisco Art Institute and at UC Berkeley. He is the author of ‚Cities in Motion’ (Stadt in Bewegung), a study on conflicts over public space in Berlin and Los Angeles (2008). Most recently, he co-edited a special issue of the International Journal for Urban and Regional Research (IJURR) on urban citizenship and the right to the city in Berlin and Tel Aviv (Fall 2015). He will be with CUNY for the Fall term 2016 and will be working on a comparative project on urban citizenship and immigrant rights in Berlin and New York.