In reply to snorbie:
It's a real shame but it was yet again flooded a few years ago and has been closed ever since.
AFAIA there was ongoing dispute over liability with the Chamonix commune over the Mt Blanc Tunnel, road flood barriers, which aggravated the flooding.
The much smaller campsite at Les Arolles on the other side of the road is owned by the same owner, Jean-Luc Burnett, who's a Chamonix Guide and very helpful.
Les Arolles is a good, clean and very reasonably priced place to stay, though it does get busy in peak season compared to the other site.
Cheers Ron