During the early 1960s, I noticed, but never read, a children's fantasy novel in the children's room of the Abington Library in Jenkintown, PA.
I think that it was a fantasy novel because the description inside the cover mentioned fairies or elves.
Anyway, I remember that the cover or dust jacket had an image of a sort of a fairy tale castle based or a medieval French chateau with white walls and blue roofs.
The castle might have been as tall and vertical as a Disney theme park castle.
But if I remember correctly it was much more symmetrical looking.
So it would have looked more like the Chateau of Pierrefonds as restored by Violet-le-Duc in the 19th century.
Or like the Louvre in the late late Middle ages.
http://historic-cities.huji.ac.il/france/paris/stroll/louvre/louvre.html
https://www.turbosquid.com/3d-models/medieval-louvre-3d-model/974358
https://commons.wikimedia.org/wiki/File:Louvre_-_Les_Tr%C3%A8s_Riches_Heures.jpg
So I hope that someone will remember a book with a cover depicting such a castle.