Unable to answer "This shop has been vacant. What’s here now?" – house number 54 – https://osm.org/node/6513805405 via StreetComplete 57.4:

Popup Store: THALESruhr. Transfer Hub for the Advancement, Livability and Efficiency of Sustainability Transformations. www.thales-ruhr.de

Attached photo(s):
https://westnordost.de/p/214845.jpg