I won't speak on the legality being that I have no experience or knowledge there, some snowblowers can definitely work on cobble stone when properly set up with skids adjusted but don't expect the cheapest electric model to cope well and anticipate extra maintenance. I'd be extra careful operating on any hill, make sure you have a good place to blow it without cars, houses, or people getting peppered with the debris they will inevitably pick up in the snow, and I don't see why it would be a problem though. Make sure to educate yourself by reading the manual thoroughly and make an informed purchase if you're going to try.