As in The Third Man, maps are a part of the establishing décor in the offices of those who police the divided city, but the lines marking the divisions are not foregrounded emblematically.
A map is also a part of the décor in the room occupied by criminals, marked with pins to signal some similitude with the plotting done by their legitimate counterparts:
At least these do appear actually to be maps of Berlin, unlike the police inspector's map in Lang's The 1000 Eyes of Dr Mabuse (see here), about which the consensus is that it is not, as it ought to be, a map of Berlin.
J. Hoberman, The Magic Hour: film at fin de siècle (Philadelphia: Temple University Press, 2003), p.11.
Hoberman's question is the one I've been asking. Is that a map of Berlin behind the police chief? I can't seem to match it to any maps I can find of Berlin c.1960, or from an earlier date. Any suggestions appreciated (email here)
'Two shots angled have been used for this map, which refer to the two perspectives that have dominated cartography historically: (1) the oblique perspective – or “perspective militaire” – has been widely used by artists since the Middle Ages, to represent landscapes. (2) The vertical perspective or bird’s eye view characterizes the more modern and scientific representation of Earth. These two subsequents views of the same map capture the passage from a classic to a more modern perspective in cartography.'
Sébastien Caquard, 'Murder and Modern Mapping', (e)space & fiction