This is historically inaccurate and ideologically charged.
"During USSR" as you say, first wave of Russian immigration settled in West Berlin in 1920s running away from Russian revolution, so you probably did not mean that period of time. During occupation of Germany by Allies, both NATO and Warsaw Pact maintained significant military presence in Germany, but in 1990 Soviets have left (feel free to check it yourself in Karlshorst), Americans stayed. There was no migration of civilian Russians to Germany at that time, but DDR welcomed workers from other countries like Vietnam. Speaking of today, you can look at statistics on citizenship of Berlin residents: there you will find that, for example, more Indians than Russians are currently living in Berlin. And of course more Ukrainians.
"During USSR" as you say, first wave of Russian immigration settled in West Berlin in 1920s running away from Russian revolution, so you probably did not mean that period of time. During occupation of Germany by Allies, both NATO and Warsaw Pact maintained significant military presence in Germany, but in 1990 Soviets have left (feel free to check it yourself in Karlshorst), Americans stayed. There was no migration of civilian Russians to Germany at that time, but DDR welcomed workers from other countries like Vietnam. Speaking of today, you can look at statistics on citizenship of Berlin residents: there you will find that, for example, more Indians than Russians are currently living in Berlin. And of course more Ukrainians.