I have found interesting article at http://www.carbodydesign.com about Renault Twingo: design history . I remember when I was in Cracow in Poland for student exchange at Akademia Sztuk Pięknych w Krakowie my professor told me this story.
One of the main inspirations of the original Twingo project appears to be the Beskid 106 prototype, developed by Polish FSM and its controlled research center BOSMAL as a replacement for the 126p produced at FSM’s plants under Fiat’s license.
The Beskid 106 was created by a design team led by engineer Wieslaw Wiatrak. Following the final blueprints (1981-1982), the first prototype was completed in 1983.
Its most original feature was the aerodynamic body with a monovolume shape. It was designed by Krzysztof Meissner, from the Warsaw Academy of Fine Arts, and underwent extensive wind-tunnel testing that resulted in a very low drag coefficient of 0.29.