Das unsichtbare Visier
The Invisible Visor was an East German television series, broadcast with long intervals between 1973 and 1979. In its first and longest season it starred Armin Mueller-Stahl in the role of Werner Bredebusch, a Stasi agent active abroad under the alias Achim Detjen.
It's a crime and drama show, and has a rating of 8.3 out of 10 from Imdb which is very high for this kind of show.
Watch it here
Not found streaming from Finland.