Som Berthiot went down in history with the Pan Cinor as the first "modern" zoom lens for motion pictures in the early 50s, being fairly parfocal and relatively well corrected. They produced many different versions over about 20 years, ranging from 3x to 10x zooms, mainly for 8mm and 16mm formats. Their zooms used a simple optical compensating mechanism with 2 elements moving together on either side of a fixed central element, which was soon superceded by separately moving variator and compensator elements in a zoom mechanism developed by Angenieux (which is still used in zoom lenses today). As such, the image quality of Pan Cinors is a far cry from modern zooms. The coatings are dated, and contrast is generally low.
I've come across quite a few with fungus, so that's something to watch for.
Having said that, the compact little f/3.8 17-85 is decent, and about as small as a zoom of this range can get, handy for carrying around on a reflex Bolex. I think it even covers S16. Pan Cinors tend to be cheaper than similar range Angenieuxs or Vario-Switars.