Vladimir Cicmanec, the fellow demonstrator who snapped the image, said he had been inspired by recent viral photos of people standing up to fascism.
"I didn't see the argument from the beginning - I was looking in another direction and a friend patted me on the shoulder - but I was just a few metres away from them," said Vladimir, who described himself as a computer programmer and amateur photographer.
"I immediately thought of that photo of the girl from Birmingham and said to myself - this could be an interesting image too. So I starting snapping away."