A military bunker located near Plougonvelin, France. This structure appears to be a Flak (anti-aircraft) bunker mounting a 2cm anti-aircraft gun, likely part of the Atlantic Wall fortifications built by Nazi Germany during World War II. The area around Plougonvelin, situated on the Brittany coast, was heavily fortified as part of Germany's coastal defense system against potential Allied invasion.
The specific designation 'Sockel' suggests this was a gun platform or pedestal mount for anti-aircraft artillery.