Landkreis Cuxhaven is seeking partners to design, build, finance and maintain a gymnasium in Langen for 20 years.
Under the plans, the partner will conduct extension works on the existing complex, with an area of 3,000sq m.
The project, which includes a convertible area of 1,250sq m, also consists of outdoor facilities, classrooms, a cafeteria and a library.
Interested parties have until 14 December to submit responses.