I found the online gallery (a German site) which is the only place where the picture in question exists (I used Google Images search by image function) and it says Ruhrpott bei Nacht, with a short comment to the beautiful colors of the sunset. The only tags for the image are landscape (on German) and Duisberg. LINK:
http://galerie.chip.de/k/still-life-technik/industrie/ruhrpott_bei_nacht/207512/
To add a final proof there are a few pictures from the Duisburg collection taken from Wikimedia
This complex (from the name Stahlwerk - I guess that this is a steelworks) is too similar to the one in the right central area of your image. Hell even the colors, number and placing of the lights on the steel furnaces is the same.
See the similarity? Don't forget the different angle and all?
There is also this complex that is quite similar to the one on the left area of your picture - here:
And to end. Why is this rotation device so familiar to me?
I think that this proves that the picture is indeed of the City of Duisburg.
I don't know where you did find it and what did it say it was but this three images when compared to the one you given, plus the gallery - the source of this picture - point that it said wrong and the picture is what it is - a sunset panorama of a part of Duisburg.