In any country that normally uses Schuko sockets, which is much of mainland Europe with a few exceptions. There's a huge range available from most German electricians suppliers. The words you're looking for are:
- Steckdose - socket
- Deckel/Klappe - lid/flap
- Schwarz - black
- Unterputz - flush mount
Kopp is a popular brand and the RCD on my boat is also a Kopp (my sockets are, unfortunately, UK ones).
Here's one (although in brown). You'll also want the
matching frame, which is sold separately because it can be combined in single, duo or triple outlets or other units (such as switches, antenna sockets, etc.).