Hey there,
There are multiple examples in Construct where this is done using 3D Objects(blocks). This would be different than using a 3D Background, though...
You might find the "Vehicle switching" template/example the most helpful to see how 3D objects interact with the camera object. But, other examples like the "3D Platforms", and others like "Gravity Portal" may give you an idea of what 3D Objects would look like from different perspectives.
I don't believe what you are asking is possible just yet(using one big 3D object, such as a background). But, you could certainly map out different 3D objects in a level, or have them spawn on set points of the background before coming into the camera's view, or set them where you want on the background.
This would allow the perspective of the buildings to change depending on the players point of view. I know this is not the exact solution you are looking for, but I hope it helps a bit.
All the Best
EDITS: Grammar, and adding info. Maybe some other folks will chime in with some ideas as well :)