Huh. So what did olavr have to say?
I was going to guess 125, but it didn't quite look like the normal home-grown Fiat. So, I thought maybe it was one of the cars licensed from one of the following countries: Poland, Yugoslavia, Egypt, Argentina, Colombia, Chile or Morocco.
But you said it wasn't a car built under licnese. That it was actually a Fiat so I took that to mean a real Italian Fiat.
So what could it be.
From the beginning I thought it looked like a 130 Berlina. But, the grill and front bumper were all wrong. And the quarter window wasn't right, either. However, the proportions looked right so I figured it must be some kind of early 130. At the same time I knew it wasn't the Opera (4-door) or Maremma (Estate) that Pinifarina was fooling around with as an extension of the gorgeous Coupe.
I was really stumped since the 125, 130 and 132 were the only viable alternatives.
So, my guess is that it is some kind of concept car while the 130 was being developed as a replacement to the venerable 2300. But, it's just a guess and it sounds like olavr had the answer. So, if you want to award the point to olavr be my guest.