The first two stanzas are not banned, but not sung anymore. What the Hungarians played was "Das Lied der Deutschen" (the song of the Germans - with the melody stolen from the Austrian Kaiser anthem

)
The third stanza of this song is the German national anthem, delared so in 1991.
When the first chancellor after the war, Adenauer, came to the USA for the first time in 1950, they played a carnival song , as Germany had no anthem at this time :

It was said that he was quite peeved about this, so that he re-introduced the old anthem in '52, with only the 3rd stanza sung.