<a href="https://en.wikipedia.org/wiki/Mainz_Hauptbahnhof" class="extiw" title="en:Mainz Hauptbahnhof">"Bahnhofplatz Mainz"</a>. The postcard, dated July 25, 1919, shows a photograph that was obviously taken before WW I. In its text, probably written by a French occcupation soldier to his sister-in-law, one can read between the lines about a tragic war background.
Unknown photographer, reproduced, restored and uploaded by <a href="//commons.wikimedia.org/wiki/User:Palauenc05" title="User:Palauenc05">Palauenc05</a>
CC BY-SA 4.0
Private archive