In germany we have the “Architektenurheberrecht”.
Architectural copyright (Architektenurheberrecht) protects an architect’s original intellectual and creative achievements, including designs, plans, and completed buildings, provided they possess a sufficient level of originality (Schöpfungshöhe).
Architects can, and have, use this to deny changes to such buildings or claim injunctive relief, removal of the infringement, or financial damages.
Installing extra cabinets would most likely not be enough to seize the house, but if he can convince a judge that it will sufficient change his art he could get a order to have them removed and the original space restored again.
Not sure if this is germany only, but it shows that every bullshit is possible when it comes to laws.
They don’t say anything against applying or installing the mod to the game, at least not in this case, but against making money with their IP. This should not be mixed together.