No obligation to have a guide. But you should be competent off piste.
And have a map, a proper map and be good at using it. Not a place to go following your nose without a very good idea of where you are.
Missing a traverse could see you at the top of a 300m cliff back into town. Following a few tracks over rolling wide powder fields and steepening terrain and chutes can put you at a pinch point needing a 30ft abseil or a 3 hour hike back up again. or death.
Just get a guide. Not that expensive if you join a group. Snowlegends, Band of Boarders (they also ski) or the Bureau des Guides. They’ll take you to the funnest places and the best snow, and you might end up having a private guide at the end of the day because the others are tired or broken.
Love the place, very special. Been a few times, once for 10 days on my own, once for the Derby de La Meije with a couple of mates (bonkers top to bottom race – Megavalanche equivalent) and once on a road trip with the wife.