Three-storied building of austere morphological elements. The marble propylon at the entrance is one of the characteristic elements of the building while the ground floor is also covered with marble and the openings in between are filled with decorating ironworks. The main entrance has a marble door-frame that ends to a decorating marble jamb. The stories are separated by a long cornice. Characteristic element of the facet is the marble balcony.
When the City of Athens got a 130,000 drachmas loan by the National Bank of Greece, it decided to built the Municipal Mansion on the last remaining area from the people's garden, on the western side of Athinas Street. The architectural study was given to the architect P. Kalkos (during the mayoralty of P. Kyriakou) and in October 1872 the construction started to finish less than two years later in May 1874.
Originally, the building was two-story high, built in a strict neoclassic style. In 1901, during the mayoralty of S. Mercouris, restoration and decoration works were conducted. In 1937 the second floor was added.
By a ministerial decree of 1989, the building was identified as a historical preserved monument since it is considered to be important for the study of the architectural history and the city-planning development of the city and because it consists a characteristic place of reference for the lives of the people of Athens.