Acerbi was angry because of the accusations of the fan during a meet-and-grreet for Inter. The fan in question mocked Acerbi, referring to PSG's 5-0 Rout from Inter in the Champions League final last month.
Acerbi sought help from a translator before he responded to the taunter.
The translator said to the fan in English on Thursday: “You have to be serious with him.”
Seconds later Acerbi came in to say in Italian: “I am serious. Don't care – I don't like it … I'm crazy, I'll defeat the S *** from you.”