How will users find the new domains? If they can reliability do so then dns is not needed in the first place. If not, then the laws are effective.
Hell, they could setup their own public DNS outside of France and suggest users use that. Users already switched from local/ISP DNS to Cloudflare / Google because of the previous law so that is not a big hurdle (ignoring the obvious security problem - many users won't care they just want to watch the game).
My point though is that these laws will be very easy to bypass just like most anti piracy laws before it. Note that The Pirate Bay is still up and running.
In many cases it was browsers changing the used resolver behind the users back contrary to OS-wide settings.