Ladies and gentlemen, I present to you yet another "leaked" (wink, wink, Ubisoft) screenshot of AC Unity
This is where it came from:
And the edited version:
The video has since been removed, claimed by Ubisoft: http://www.youtube.com/watch?v=-NriQlHzoA4
I don't think it's concept art, I'm certain it's gameplay. I think it look pretty damn good! Ubisoft will probably be releasing some new footage very soon.
The street closely resembles that of the one in the official trailer: