The entrance building was largely built of sandstone under the direction of Otto Peters and Osmar Dürichen and is dominated by the lobby. Its large arched windows and columns are flanked by two imposing entrances. The two side wings, however, are rather simple. The facade of the entrance building on Schlesischen Platz, which has a total length of 177 metres, is a strictly symmetrical structure, with the exception of the balcony-like extension at the right end, which was originally the entrance to the royal apartments. 2,040 cubic metres of sandstone was needed for its construction.