It is based on a real house if you didn't know.
See here and
here, for example.
In Benoit Peeters book, there is a anecdote about when Hergé and some assistant (Jacobs, de Moor or someone else, don't remember) were at the real house, making some drawings, and just when they leave a black car drives up to the house. They later find out that the house was the head-quarters for the Gestapo (or S.S. or somesuch).
If Hergé had been spotted drawing pictures he would probably have been taken in for questioning and the house for the Professor would surely have been a different one!
None the less, I also likes the house, even before I read the history of it. I think the odd angles makes it fascinating.