A promise by Fiat Chrysler Automobiles to deliver 5 billion euros ($5.6 billion) of savings in its merger with Renault without closing plants looks audacious to some analysts, given the Italian automaker's surplus capacity in Europe.

The pledge goes further still, however. Asked Thursday whether job cuts will be needed, Renault Chairman Jean-Dominique Senard -- who would run the combined company as chief executive officer -- said the deal "doesn't call for human sacrifice."

The Italian automaker has confounded experts before, under former CEO Sergio Marchionne. This time, there is good reason for skepticism. Despite years of belt-tightening, both Fiat and Renault have spare capacity close to home. Almost one-third of Fiat's global work force of 198,500 was based in Europe at the end of last year, even though the maker of Jeep SUVs and Ram trucks earns almost all its profit in North America.

Renault, which counts on Europe for more than half of sales, leans on its partnership with Nissan -- strained in the aftermath of the Carlos Ghosn affair -- to keep plants such as the Flins facility north of Paris busy. Making matters worse, demand in the region is sagging.

"I don't know if Fiat will regret their statement, as both companies have plants that are heavily under-utilized in France and Italy," said Kevin Kelly, a consultant at Frost & Sullivan who worked on Renault-Nissan's powertrain strategy until October. "As a merged organization, it becomes even more likely that some plants will have to shut."