The people are walking on Niederkirchnerstrasse, the former No Man's Land area in front of the final wall, what we in the West saw as The Berlin Wall. You can kind of see that the Wall has been heavily damaged ("souveniered") prior to it's designation as a historical monument.

Earlier in the day I'd been on a bus tour around the city; the bus came down this street and I realized nearly instantly that the building to the right was the building in the background of the first 1988 Wall photo in this gallery.

Quite a revelation for me.