The German seal of approval DGNB was developed by the German Sustainable Building Council and the former Federal Ministry of Transport, Building and Urban Affairs in 2007. Over the past years, the seal was supplemented by diverse types of use and updated in line with the developments in the energy policy as well as standardisation. The DGNB system has an international version which allows it to be used world-wide. The valuation of the real estate is based on 6 theme areas: