In reply to dave o:
Saw the finish in Pau in 2012.
Get a spot as close to the finish as you can - that way, you'll have big screens to see what's going on with the riders and there'll be a bunch of over-priced souvenir stands.
You wouldn't believe the carnival that rolls through ahead of the riders - team buses, sponsors wagons of all shapes and sizes, girls on rollerskates chucking out freebies, etc, etc, etc. If you're near the finish, you might see some famous people that aren't riding - we saw Chris Boardman giving interviews. There were also a bunch of kids races down the finishing straight.
Only downside for us were the seriously pissed up Norwegians singing lewd songs about Boasson Hagen at the top of their voices.