The Lives of Others (Das Leben der Anderen) (German)
“In 1983 East Berlin, dedicated Stasi officer Gerd Wiesler (Ulrich Mühe), doubting that a famous playwright (Sebastian Koch) is loyal to the Communist Party, receives approval to spy on the man and his actress-lover Christa-Maria (Martina Gedeck). Wiesler becomes unexpectedly sympathetic to the couple, then faces conflicting loyalties when his superior takes a liking to Christa-Maria and orders Wiesler to get the playwright out of the way.“
Another one that’s just scary was the German film “Death Tunnel” I believe.