This article consolidates critical urban sociology with the understanding of cultural sustainability towards urban development. Whereas the latter demands a 'culture of complexity' based on self-organized creativity as stipulation for a sustainable creative city, the former provides theories for analyzing unsustainable creative cities. By combining paradigms from critical urban sociology and cultural sustainability this article lays ground for understanding urban social movements by artists. On the one hand these movements resist unsustainable urban development; on the other hand they strive for opportunities that allow urban communities becoming creative sustainable neighborhoods. Lefebvre's 'Right to the City' concept, Molotch's 'growth machine' thesis, and Smith's elaboration of 'gentrification' are particularly suited to explain the unsustainable urban development of 'creative cities'. The contrasting term of 'cultural sustainability' combines ideas of 'sustainable creativity' with concepts of resilience and serendipity; here, urban development is not limited to mono-causal economic objectives. The theoretical considerations are illustrated by three case studies in Hamburg, Germany, a city with a neo-liberal, i.e., unsustainable, urban development strategy. The cases demonstrate ranges of crossovers of artistic, social and political objectives. They represent degrees of resilience against an unsustainable urban political economy with an unsustainable grasp on creativity. They also represent degrees of adaptation towards urban cultures of creative sustainability with needs of limiting growth, fostering social solidarity and shaping realms of creative possibilities.