Providing indoor navigation within a building is usually associated with large investments in infrastructure. We present and evaluate an approach to provide indoor navigation with minimal infrastructure investments. In our approach people use a mobile camera device like a mobile phone as a magic lens. When the device is sweeped over a map of the building, the way is augmented on the camera image of the map. We show that people using our system use more maps and make less errors. The main advantage of our approach is that no tracking of the user is needed - the navigation is solely based on the user's mobile phone and paper maps.