The remains of the castle can be visited
Château du Burgstall

The Château du Burgstall is a castle ruin located in Guebwiller in Upper Alsace, France. Long believed to be lost, this site was only rediscovered in recent times.
History+
The origins of the Château du Burgstall date back to the late 12th or early 13th century, when the castle was built. Documentary mentions are rare, which led to the assumption that the site had been lost. It was only in the 1960s, during the construction of a supermarket, that parts of the ruins were uncovered and rediscovered.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://en.wikipedia.org/wiki/File:Ch%C3%A2teau_du_Burgstall.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 47.9108, 7.2097