In reply to markokeogh:
Was there for 2 months in the Autumn. No trouble from anyone and plenty of friendly people also staying in their vans.
However in Chamonix itself there's not many nice and quiet spots to park up. Would imagine it'd be even worst in summer, but in September and October it's still crazy busy. Perhaps I'm too used to the highlands though!
There's a public toilet and sink at a parking spot on the way out of town towards Argentiere, otherwise Les Galliands had a toilet (although it's locked a lot of the time).