The war of words started at the unveiling of the electric Fiat 500e (pictured top) at last month's Los Angeles auto show when the Italian company's head of product marketing, Matt Davis, fired a shot at the design of the Nissan Leaf.
"Let's be honest, ugliness is probably one of the worst forms of pollution," Davis told Bloomberg.
"The Fiat 500e proves that you do not have to give up on good looks to deliver an electric car."
Unprepared to simply cop the criticism on the chin, Nissan head of global marketing Simon Sproule returned fire, telling industry journal Automotive News Europe that Fiat has not exactly shied away from “controversial styling” in recent years.
"Many would describe many of their products as visual pollution,” Sproule said. “Take a long, hard look at the Fiat Doblo (below)."
Sproule also took a shot at the 500e – a car designed specifically to meet California’s emissions regulations that will not be sold in Europe.
“They chose the smallest vehicle in their range with the least amount of passenger functionality.
"I don't think they have the credibility or the hardware to stand behind these kind of statements. Either you're committed to it or not."
A Fiat spokesperson declined to comment in response to Sproule’s remarks, potentially signifying a ceasefire between the two.