These T adaptors were officially banned but were still around on flea markets and imporiums.
They're theoretically banned here too, but still in wide use, even the smaler ones that are really bad (tend to wear loose and arc).
Everybody who works on old equipment likes to have those, since they allow to plug old round plugs (like on my lamp) into Schuko outlets. Nice for old radios and stuff.
The switch with the glass plate is interesting, never seen those before.
They seem to have been common in the 1920s and 30s, even in less than upscale homes (municipial housing to be precise).
Berker still makes them, €100 a switch I think.
@kenbo: what are you talking about? the flat plastic stuff or the twisted cloth from the lamp?
Believe me, I checked the rubber of that braided cloth cord _real_ close before plugging it in! It's not brittle at all and has no signs of mechanical damage. That stuff is incredibly flexible!
The wiring in the walls is part original 1913 cloth wire, part 1960s wire in conduit. Everything is on a 30mA RCD.
I believe originally there were two switches where the white one is now, but at some point they were split up and now there's one switch to either side of the door. The wiring for two lights or a split chandelier is still in the ceiling.
This kind of Schuko socket can be widely found in 1950s houses. Older ones sometimes have them in the kitchen. They have a porcelaine body and are close to indestructible.