The cheese shop Bellevaire on rue St. Antoine near rue St. Paul in the Marais (4th) put out their tartiflette cooker today. I don't know about their other branches.
I have never liked tartiflette, in part because I've only tried it a couple of times from little Xmas booths in Paris. Way too gloppy/cheesy. I have to say it was a lot better at Bellevaire. They use good, raw milk roblochon, for one thing. There is also more potato and lardons and less gloppiness.
Still, it is a bit too fat-cheesy for me to have more than a few bites.