Modern, sustainable urbanism is a complex task and has to satisfy a lot of demands: An energy supply emitting the less possible CO2, an efficient and environment-friendly mobility, socially and culturally attractive districts, moderate prices for the satisfaction of that basic need which housing is.
Freiburg, "Germany's most sustainable big city" (2012), has to meet these challenges as the city is growing and needs housing. in 2019, the city of Freiburg created the department "affordable housing". One of the strategies of the city is to build new districts with "common wealth" investors (cooperatives e.g.). This is happening in the fourth eco-district "Kleinescholz" which is currently under construction. The blueprint for this strategy, and for a carreduced mobility and a high quality of public ground, are the two eco-districts Vauban and Rieselfeld. The existing districts are also renovated and revaluated with an intense civic participation, e.g. in the social housing districtWeingarten, where the first highrise in the world was renovated to passive standard.