Based on the very vague estimate I'm getting from the 37 min gameplay video, I seriously doubt that.
What I do believe is that Novigrad will be the biggest city ever seen in a game that isn't focused on one to begin with. It might sound a bit less impressive when I write it down like that - everything sounds less impressive when you begin to specify the categories. But to me it's still amazing. The size of the city, considering it's not the focus of the world, is stunning. I mean, the only ones which I think compare are the cities in AC, but the series is focused on cities, and GTA (which is also mostly focused on cities).