This is a wall mount for OBI Funksteckdosen Set (manufactured by Emil LUX). See this GitHub thread for more information about this kind of 433MHz RC switchable plugs and their remote control. Other RC switchable plugs, such as the Brennenstuhl RC CE1 4001, have a very similar remote that might be compatible. The underlying 433MHz OOK protocol is known as quigg_gt1000 in pilight, but the remote for the Quigg GT-1000 appears to have a slightly different shape.

Print standing up with supports if needed. Keep the seam to the back of the holder for the best possible appearance. Since the remote is very light, I used thin outer walls (0.8mm) for the holder to save on filament and print time. Add mounting tape to the pockets on the back of the holder, then stick it to the wall.

Parametric FreeCAD model for customizing to your remote is also included.