The Palazzo Pubblico's ground floor houses the offices of the town hall, but its upstairs chambers, frescoed by the city's foremost artists, have been transformed into a Museo Civico (municipal museum).
The Municipal museum is situated in a building across the street from the Palazzo Pubblico. 
mnli hypothesis: The Municipal museum is situated in a building across the street from the Palazzo Pubblico.  premise: The Palazzo Pubblico's ground floor houses the offices of the town hall, but its upstairs chambers, frescoed by the city's foremost artists, have been transformed into a Museo Civico (municipal museum).