The unique premises of the City Mayor’s Residence are considered an artistic and architectural gem in the art deco style. The residence of the Mayor was established in the years 1925-1928 by architect František Roith and occupies the entire first and second floor of the front tract of the City Library at the Mariánské square. The premises are used for representative purposes and receptions of distinguished guests in Prague. They are open to the public only on open-door days.
Source: https://www.prague.eu/en/object/places/2779/the-lord-mayors-residence-rezidence-primatora