Named after the poplars (‘Pappeln’) on this small triangular square.
The square has had its name since 1870. It lies north of Invalidenstraße, bordered by Bergstraße, Ackerstraße and the wall of the Sophienkirche parish cemetery. Besides its poplars it has the Geldzählerbrunnen (‘money-counter fountain’) by the sculptor Ernst Wenck, set up in 1912.