Man, I hope this won't be removed for lack of enough sources. The execution of Eddie Slovik was conducted in a private home situated at 86, rue du général Bourgeois in Sainte-Marie aux mines. (copy of the official report, signed by Lieutenant Colonel Sommer can be found here: http://www.commandposts.com/2013/01/january-31-1945-the-execution-of-private-eddie-slovik/). The building was torn down and replaced by a more modern building which used to house the local gendarmerie. Which is also gone.

edit: Eddie Slovik's execution was the only one conducted here. Of course, if I4m wrong, I welcome corrections. That's all Ask historian's all bout, right?