At retropeugeot.com there is a French catalogue, believed to be from 1974. Under the Nouveau Style section are the following models:
(various accents omitted)
NSA 22. Routiere luxe, cadre mixte largement, ouvert, de conception nouvelle et originale, en
tubes a section ovale, avec gaines incorporees. Roues de 550 A, pnues bicolores 1/2 ballon,
moyeux en metal leger, guidon et tige de selle a reglage instantane, garde-boue inoxydables,
porte-bagages AR et bequille chromes.
NSA 40. Meme modele 3 vitesses.
PNSA 22. Version pliable de NSA 22.
PNSA 40. Version pliable du NSA 40.
NSL 22. Routiere grand luxe, freins a tirage central, garde-boue et pare-chaine inoxydables,
bequille et porte-bagages AV et AR chromes avec serre-paquets sandow.
NSL 40. Meme modele 5 vitesses.
PNSL 22. Version pliable du NSL 22.
PNSL 40 Version pliable du NSL 40.
As far as I can see, P= pliable or pliant, ie. folding frame.
A = base model (luxe)
Frame from oval tubes, cables in the frame, 550A size wheels, whitewall tyres, light metal hubs, seat and handlebars instantly adjustable, stainless steel guards, rear luggage rack.
L = luxury (extra luxury), has an extra luggage rack and elastic cords and centre-pull brakes.
For some reason, the 22 changes to 40 if it has gears, the NSA 40 has 3 speeds, NSL 40 has 5 speeds.
I believe all the ones I have seen in Australia have been PNSL 40 variety, a one-speed I saw seemed to have once upon a time been 5 speed, it had the two luggage racks.
There is also a NJ - junior with 500 size wheels, also with L or P varieties. I believe I have seen one of these in Australia. NJD is 3 speed, PNJ and PNJD are pliable (folding) versions.
A comment was made below about a FU 22/5: