The employees were dismissed after “hanging” a cardboard cut-out, featuring a photo of Marchionne, and then carrying out a fake funeral in front of a company factory in Nola, near Naples, La Repubblica reported.
Fiat said they had violated “the most basics requirements of the employment relationship”.
The incident happened during protests in early June against layoffs as well as to demand the return of more than 300 workers to a plant in Pomigliano, also near Naples, after they were posted to Nola in 2008.
They enacted the fake suicide after the real suicide of a factory worker, Maria Baratto, who died at her home in Acerra in May.
Three workers from both the Pomigliano and Nola plants are reported to have committed suicide because of "layoffs and the precarious economic and social situation", La Repubblica reported.
Marchionne was hailed a hero at the start of this year for orchestrating the takeover of US car manufacturer, Chrysler.
On January 1st, he sealed the deal to buy the 41.5 percent of Chrysler that Fiat did not already hold, after months of tough negotiations.
At the time, he also pledged to rehire all of Fiat’s 31,000 assembly workers by 2015. Two- thirds were put on temporary leave in 2013 for an average of four months.