Below the street level, Japan Center has four basement levels, above all an underground car park. Japan Center itself consists of a transparent base zone. The first floor was designed as a meeting space for events and offers a total of four conference rooms that can accommodate up to 360 people. On the second floor is the lower building management center, followed by 21 office floors with a lettable area of 26,900 square meters (289,549 square feet). A second building control center is located on the 24th floor. On the 25th floor is a restaurant that serves as a canteen. In the skyscraper head of the Japan Center there are two further office floors and other technical installations for the upper floors installed.
Originally, Japan Center was primarily intended for Japanese companies. Due to demand, the office tower has since been leased to various companies. Meanwhile, the European Central Bank (ECB) is the main tenant and uses all of the total rented space. The ECB’s lease expires in 2025. As there is insufficient space at the headquarters of the European Central Bank for employees of the Single Supervisory Authority, these employees work in the former headquarters of the ECB in the Eurotower on Willy-Brandt-Platz. The ECB’s lease at Japan Center was originally intended to last only for the duration of the upcoming refurbishment of the Eurotower, but was extended in 2015 to 2025. The lessor is GEG German Real Estate Group AG.