So you're asking "what do I look for when inspecting a vintage bike with intent to purchase" ?
Firstly are you after a machine to ride? Or something old to collect and store? Because the requirements are totally different
The wheel size will be 27" in steel from new, or it could have been swapped out with 27" alloy or 700c alloy or steel. Read the sidewall of the tyre/tire to know. 622 means its a 700c, and 27" means pretty much that. It could also have 28".
Frame - take a small magnet with you Even a fridge magnet will tell you if a part is ferrous and therefore steel. The frame is most likely steel.
If you're buying for a collection, you want original everything. Papers, receipts, booklets, anything it came with. Original running gear in poor condition is more collectable than incorrect running gear
On the other hand if you want a bike to ride, 200 euros seems a lot for an old bike. It has to fit your body size and shape, and then everything else comes afterwards, like looking for corrosion, pitting in bearing races etc.
Some Peugot specific info on this page: Vintage Peugeot tends towards the left when riding
And this one should be a leader https://marksbikes.wordpress.com/2011/01/09/bike-mysteries/