Well it does look like digital concept art first and foremost. You could say it's influenced by 19th-century impressionism (closer to post-impressionism). These works were always oil on canvas and the artists tried to convey their ideas without necessarily over rendering the image as you would with realism.
It's a good fit for digital concept art since it too is about conveying ideas quickly.
I hope this helps. However, you might have trouble finding free CC works like this depicting a modern city at night. I wish you luck.