From 1993, conversion plans were prepared for the transformation of a former barracks in Freiburg, Germany, to a new sustainable city district for approximately 5,500 inhabitants and 600 jobs. The city of Freiburg bought the 0.41 km2 area from the federal authorities. The main objective was the realization of a sustainable urban development project, meeting ecological, social and cultural requirements based on the principles of cooperation and participation. The public organization ‘Forum Vauban’ coordinated the participation process in the district’s urban planning from 1995 to 2004. The first citizens moved into the district in 2000. The district’s construction process was completed in 2014. The main objectives of the Vauban urban development project related to: mixed-use (balance of working and living areas), sustainable transport (car-free living, priority for walking, cycling and public transport), nature conservation (protection of existing natural areas), mixed social groups (balance of low-, middle- and high-income groups, families, single people, elderly people), diverse urban typologies (renovation of existing buildings, new constructions with comparatively high density, development of small building plots by public and private builders, and cooperative building projects), sustainable energy (highly energy efficient buildings, renewable solar energy production, decentralized combined heat and power generation, and short-distance heat distribution networks), sustainable materials (use of ecological building materials and reuse of existing buildings and infrastructure systems), sustainable water and green infrastructure (decentralized rainwater management, ecological sanitation systems, green roofs, public green spaces), and participation (involvement of local residents in the design and planning processes).