The increasing number of media facades in urban spaces offers great potential for new forms of interaction – especially for collaborative multi-user scenarios. In this paper, we present a way to directly interact with them through live video on mobile devices. We extend the Touch Projector interface to accommodate multiple users by showing individual content on the mobile display that would otherwise clutter the facade’s canvas or distract other users. To demonstrate our concept, we built two collaborative multi-user applications: (1) painting on the facade and (2) solving a 15-puzzle. We gathered informal feedback during the ARS Electronica Festival in Linz, Austria and found that our interaction technique is (1) considered easy-to-learn, but (2) may leave users unaware of the actions of others.