As a bit of forward information the Tour De France starts in Liege, Belguim, on Saturday the 3rd of July and runs around Belguim and NE France until the Wednesday when it starts to make its way around France.
For those who have not been caught-up in the Tour before, the Gendarmes close a rolling section of the road some 4 hrs before the riders come through, so a long wait if you need to get somewhere. 
For those who have seen it - whether planned or not - it is quite a sight, and everything, I mean everything takes a back seat where the Tour comes through.
Take a look at this link for full course details.Site officiel du Tour de France 2024
Hope this information is of help,
Cheers