germany-düsseldorf: building-cleaning services./ cleaning services./ the client manages the museums in düsseldorf with the houses k20 grabbeplatz and k21 standehaus. due to the importance of the buildings and the quality of the exhibits exhibited there, extensive services in the sense of maintenance cleaning services (hereinafter "services" or "cleaning services") must be provided in the buildings. the subject of this tender is the work agreement for the provision of maintenance cleaning services k20 grabbeplatz and maintenance cleaning services k21 standehaus