The journalist had to be examined at a hospital after the attack but was only slightly injured.
One 28-year-old man, the main suspect in the assault, and two of his companions were arrested. Police are investigating them for causing bodily harm.
Dresden authorities no longer supply numbers for participation in Pegida ("Patriotic Europeans against the Islamization of the West") rallies, but student group "Durchgezählt" (counted) estimated that between 4,750 and 5,500 people turned out onto the Theaterplatz for the gathering.
Recent weeks had seen up to 8,000 people on the streets for the movement's Monday-evening meetings.
And in October, 20,000 people gathered for Pegida's first-anniversary rally, which also saw several journalists attacked.
Around 800 people took part in a counter-demonstration organized by Gepida – short for "Irritated local people protest against the intolerance of Dresden outsiders".
Police said that 400 officers were deployed to keep the peace.