Only painted 3 night paintings in my life.  Very difficult to do in Watercolour in my opinion, and the trickiest decision - how to paint the bright lights on the walls of the building.  Also, you would think the buildings will be lighter than the sky?  Maybe not in some circumstances as in this scene - really just after dusk rather than the middle of the night.  I might try again but find a different way to preserve the light of the lights.