Well done for earning the point Alfa Japan, although I have to say I'm having trouble seeing the correlation between your reply suggesting Viotti and the fact that you have solved the puzzle!
I thought it was a very good puzzle and didn't know the answer (I thought maybe Boano because they were involved in the design of the Simca 1000, which this car does resemble as SACO says, but I would have been wrong) but the answer seems to have been given by SACO himself that the car was designed by Fiat Centro Stile..