The teenage students - Mohammed Gharbawi, Ali Reza Gharbawi and Massoud Afrawi - were humiliated in front of their classmates in a violent and organised attack at Faridneya School, Ahwaz City.
The shocking video of the punishment, which is illegal under educational regulations, reveals the racist child abuse in the Iranian education system. Ahwazi Arab youths under-achieve at school due to discrimination and being forced to learn in Farsi, a language that is not their own.
A spokesman for the Ahwaz Centre for Human Rights said: "The punishment is for students who don't do their homework or who get low grades in the questioning exams in class. Whatever they have done, they should not be punished like that, according to educational regulations. But away from observers, Arab students get this punishment, so you can imagine how those with such a mentality deal with prisoners."