The Harlem Shake video produced by students at a language school in Tunis looks familiar enough. There is a boy with a cardboard box over his head dancing wildly, a girl in a dressing gown jumping up and down, a mass of hair bouncing with her.

What you do not see though is the group of conservative Salafists who turned up to try and stop the students. “Our brothers in Palestine are suffering while you are dancing!” one of the Salafists called out.

Fights reportedly also broke out between Salafists and would-be shakers in Sidi Bouzid, the town that kicked off Tunisia's revolution in 2010. Internet sites associated with the conservative Islamist movement in Tunisia condemned the Harlem Shake dance as immoral and indecent.

What started as a comedy internet craze has turned into a debate about liberal vs Islamic values in post-revolutionary Tunisia. To many of the students involved, the Harlem Shake has become a litmus test of social and cultural freedom. Already, an art exhibition deemed to be blasphemous and Sufi shrines considered heterodox by hardline Muslims have been attacked.

The debate deepened when the Minister of Education got involved. Abdellatif Abed, from the centre-left Ettakatol party, said he would investigate a group of teenagers who filmed their own version on school premises. In response, supporters of the students called for a mass Harlem Shake protest outside the ministry last Friday. A few dozen braved the rain to dance and sing the national anthem – and another protest is planned.