Museum Plantin Moretus is a located in Antwerp, Belgium. Plantin Moretus was a printer. He sold his company and house to the city of Antwerp in the 19th century to be turned into a hotel. Plantin Moretus started in the 16th century.
The interior hasn't changed since these postcards were made (in the 1930s).
Links:
museum.antwerpen.be/plantin_moretus/index_eng.html
en.wikipedia.org/wiki/Plantin-Moretus_Museum