This humble advert contains a decent spread of information. The Nivex is available:
- 'Avec ou sans pattes'. In my ignorance, I would normally translate this as 'with or without a derailleur hanger plate' but I am not quite sure what it meeans here.
- For 3 to 5 speeds plus a 'point mort', which I take to be the dummy sprocket that you fit the chain onto when removing the rear wheel.
- With a clamp on collar, or with a braze on fitting.
The drawing illustrates how you can remove the rear wheel without touching the chain.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)