"Scandalous!" Retorted Phillipe Martinez, the secretary general of France's hardline CGT union on Tuesday, in reference to comments made the day before by the head of Medef, Pierre Gattaz.
"It can go as far as defamation and we're taking it very seriously", Martinez added.
On Monday, the Medef boss added insult to injury by calling CGT union members "thugs", and "terrorists", in an interview with French daily Le Monde.
Gattaz accused the left-leaning union of becoming radicalized and putting their own interests first before that of the country; this, especially since Philippe Martinez took over at the helm.
His comments haven't just angered a section of the unions, but also leading political figures withing the ruling Socialist government.
Among them is deputy Pascal Cherki. He described Gattaz as a "pathetic guy" on Twitter, calling him "stupid", and has exhorted authorities to condemn his statements.
In a country still reeling from the impact of last year's terrorist attacks, the use of the word "terrorist," however appropriate, is bound to cause some upset.
Meanwhile, Myriam El Khomri, the author of the controversial bill, has distanced herself from the head of Medef, saying "I would never employ such language."
The ill-fated bill is set to be debated in the Senate on June 13th.