Schönbusch Palace is located on a slight elevation above the lake, with a direct view of the Johannisburg residence. This small Neoclassical summer palace was designed by the architect Emanuel Joseph von Herigoyen (1746–1817 for the Mainz electoral bishop Friedrich Karl von Erthal (r. 1774–1802); construction began in 1778 and the interior was completed in around 1788. The other buildings in the Schönbusch landscape park were also designed by Herigoyen.
The rooms illustrate the princely life style towards the end of the 18th century. They are decorated with stucco-work and still have their original, Louis Seize-style furniture. The wall coverings were reproduced on the basis of remnants of the original material dating from around 1780.
The entrance hall with its four large sandstone columns but in particular the hall on the first upper floor are highlights of early Neoclassical interior design. Here the walls are decorated with stucco pilasters and the ceiling is divided into sections in a variety of colours and stucco-work designs, which contain figurative scenes.