In the northwest of the city, the Park Monplaisir was created around 1700 according to the French model. Markraf Philipp Wilhelm had the first garden palace and water systems built. The following margraves continued to design the park and replaced the summer palace with new buildings. The current massive building dates from 1778–1780 and is the third castle on this site.
The 16 hectare park used to include ponds, rondelles and arcades, pheasantry, sculptures and even a deer enclosure. The paths were star-shaped at the eight-way star from the main avenue. An approximately two-kilometer-long avenue planted with linden trees and chestnuts led from the city palace to the palace and park in Monplaisir.
After 1800 the building was used as a gardener's apartment, later as a guest house and as an excursion restaurant. Around 1821 Peter Joseph Lenné participated in the design of the park.
Around 1953 the building was extended by one room - used as a ballroom and even as a canteen for the oil processing plant. The building was renovated at the end of the 1970s and reopened as a high-class restaurant. The hall extension was set up for the self-service of garden guests. In the 1990s the castle stood empty until the Prussian Cultural Association Monplaisir e. V. was founded in 2004 and dedicated to the restoration of the Parkschlösschen. Now the Monplaisir castle can be used again for events and gastronomy. (currently closed)