hummmm .....zenit clone ? my opinion is : that camera was straight derived from Mometta Junior or Momikon III (same shutter and button , 42 screw mount too) same philosophy as first zenit.
Yes, I believe Alain is correct. I have Zoltan Feger's fine book about the Hungarian cameras (fortunately in English as well as in German) and he seems to say (page 119) that this prototype reflex camera was designed from:
"A natural starting point was the design of the Mometta III and Mometta Junior that took shape at the same time."
The "(H)UNIFLEX - HUNGRETTA prototype of 1957" (as this same photograph is captioned ... the same photo that Luiz used in his WIKI entry, from "HUNGARIAN CAMERAS" by Zoltan Feger, page 125) is an original design, not a clone of Zenit!