Approval in individual cases (ZiE) for carbon reinforced concrete components in semi-precast and prefabricated construction in the BOX part of the CUBE building. At the end of September 2022, the world's first building made of concrete was opened at the TU Dresden, in which exclusively continuous fibre-based reinforcement, mainly made of carbon, was used. For the construction of the BOX part of the CUBE building, an application was made to the Landesstelle für Bautechnik (Leipzig) for an approval in individual cases (in German: Zustimmung im Einzelfall, ZiE) and a project-related type approval according to the Saxon Building Code. In Part I of the ZiE, the building part BOX of the CUBE was ruled. The mechanical parameters of the individual carbon concrete components and the mathematical procedure for determining the serviceability and load-bearing capacity of the carbon concrete components were defined. In addition, the ZiE allows the use of non-regulated, new types of thermal insulation and defines parameters for the calculation of thermal protection and energy demand for the building. In the article, selected investigations on the carbon reinforced concrete components of the BOX are presented, which were a basis for the ZiE.