The remains of the Castle can be visited
Château de Greifenstein

The Château de Greifenstein is a castle ruin in the commune of Saverne in the French Bas-Rhin department, situated at an altitude of approximately 379 meters above sea level.
History+
The origins of Grand-Greifenstein date back to the first half of the 12th century. It was likely founded by the knight Meribodo de Greifenstein, who maintained close ties with the Ochenstein family. Petit-Greifenstein emerged later, towards the end of the 13th or beginning of the 14th century. The site has been listed as a Monument Historique since 1898 and is owned by the French state.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://en.wikipedia.org/wiki/File:Grand_et_Petit-Greifenstein.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: 48.7357, 7.3340