Sorry, the discussion was in English:

Meanwhile, I found two more similar locations (https://www.openstreetmap.org/node/7020783478 and https://www.openstreetmap.org/node/3871120546).
These are stored with amenity=safe_deposit. This seems like a useful tag. I have now also stored "Safes" this way and referred to the other locations in the description.
I will leave this comment open for feedback, but will close it in the foreseeable future if there are no responses.