I've never been to the Arc meeting and am thinking of going this year. Does anybody know the best place to get tickets? That's if it's still possible!
There are ways to buy tickets in advance and despite there not officially being any enclosures in egalitarian France you can get advance tickets to an area on one side of the parade ring; however, as Ron stated, you can just go to the ticket windows at the track on the day and buy a ticket for eight Euros (Arc day).