It's hard to tell from your photos but, those look like the folding frames that were super common in the 60s and 70s. I had one that was branded Amica. If in good condition they can be fun little bikes. Most of them were made in Italy and will have cottered cranks with and Italian threaded bottom bracket, which makes changing it out not the easiest thing in the world.
This is the one I had after lots of heavy modifications
The original design was apparently not patented so it was copied by dozens of bike companies in Italy and Germany (and others). I've see quite a few, owned a Bianchi version with inox fenders (stainless steel), brazed on generator and brazed on brake levers. You will see some variations in the frames, mostly the rear end. Some have stays shaped like a rack to carry bags. They are okay for short rides only. $100 max per bike in good or great condition. You may need to swap out inner tubes as some have oddball valve stems (not Presta and not Schraeder). For the age, the tires are probably shot. Mine used standard size 20x1.nn. If they were made for the French market, they might have some obscure metric size like 400c or 450c. Check the tire sized closely before buying.
How much did he say? I've heard others tell me outlandish prices for some bikes. Some can be verified with dated price lists on the www but it never helps to argue with a seller. i'd guess most of these folders retailed for well under $100 in the 1960s.