I've rebuilt several French bikes - Mercier 300, Peugeot PX-10, Peugeot P8, Follis, etc. Working on the bikes isn't difficult, in and of itself. But as already noted, it can be a real challenge to find tools (or at the very least, a viable workaround), and especially challenging to find parts. One important question that bears asking - and this is because I can't see the dropouts in the photos provided - are you going to need an RD hanger? A lot of Peugeot frames have been drewed for some reason and hanging a derailleur can be interesting (to say the least) if someone has had a go with a grinder! (Take this as the words of experience!) I really love the way my Peugeot frames ride, by the way. You just need to ask yourself if it's worth the time and expense. I guarantee this $20 frame is going to cost a couple hundred bucks for fork, bars and stem (yes, those are special sizing too), French pedals, front and rear derailleurs, Mafac (or similar style) brakes, and so forth. Best wishes, and please post some photos if you decide to trick this ride out.