Translation of the French description at the bottom of the poster:

Directly inspired by the Château De Cheverny that Hergé discovered in a tourist brochure that described this architectural jewel of the Loire Valley. The Château De Moulinsart has become a mythical place for Tintinophiers and they cannot prevent themselves, while visiting the former residence of the Governer of Blois, feeling that they too are at Moulinsart. 

40cm (15.8") x 60cm (23.6").  Tintinimaginatio (Moulinsart) 2020