AFAIK it did and as far as old wiring is concerned still does. TN-C systems were legal until 1990, whereas Western Germany prohibited them some time in the 1970ies. On the other hand Eastern Germany started requiring RCDs in bathrooms quite a bit earlier. They had some kind of extra shallow boxes for their concrete buildings and they invented some weird kind of Diazed fuse size. Aluminum wiring was sometimes used in residential work. Other than that GDR electrical components mostly look slightly weird, but work exactly the same (e.g. the switch rockers had a slightly different shape, but for that, they look the same in Greece and the UK, so that wasn't typically GDR). I've seen GDR kWh-meters for sale here and they seem to work fine. In Eastern germany you'll still see much older wiring than anywhere else, for example I remember many real old surface-mount conduit systems, both from personal experience and from old movies.
