Indeed, the colours (blue background, middle bricks, bright pavement) help creating the 3D-effect. I did not consider B&W for that reason.
The pic was already cropped to 5:4 proportions (I need the vertical proportion), so to further eliminate the OOF foreground I also had to eliminate some of the left side. Here's the result. Of course, cutting the shadow was out of the question. Thanks for the suggestion.
* edited - attachment resolution too low by mistake? It was visible even in the downsized version *