They had to reserve slots for French riders because traditionally there were a lot of French riders that only did the qualifications in PBP years. It's in everyone's best interest to have as many French riders as possible to maintain popular support for the ride. Which is flagging, I think.
That's an interesting picture of the barn. I have heard of people making sleeping accommodations for riders. There was one family just outside of Ambrières-les-Vallées that had a couple of beds made up outside of their garage. I stopped in for a biscuit, it was fun talking to them even if they were trying to talk me into quitting the ride
They are too close to Villaines-la-Juhel for it to make much sense to stop.
There is a bar in Trévé (I think) just outside of Loudeac that apparently will let you sleep there. But you have to know about it.