The decision was issued by Dresden's town hall on Friday, after a man named as Benjamin H. applied for permission to hold a rally on Monday evening, according to a report in Tagesspiegel.
The rally was planned to protest a protest by the anti-Islam Pegida movement taking place on the same evening.
But Benjamin H., who has previously organized multiple protests against Pegida - which was founded in Dresden - and the far-right AfD party, was surprised by the reason given by authorities in their response.
The public order office could not allow the protest to go ahead, they said, because "the possibility of snowballs being thrown cannot be excluded".
Previous demonstrations had seen snowball fights break out in the city, the authorities claimed in their decision.
Benjamin H. had already agreed to numerous restrictions from the authorities, including not using a loudspeaker van, and that protesters would not bring whistles. He had also followed the authorities' restrictions over the location of his rally, to be held in a small corner of the central square, far from where Pegida's supporters would be gathering.
According to Tagesspiegel, he voiced fears that "the whole culture of protesting will go down the drain if you are only ever allowed to stand in the corner".
Authorities argued that since the meeting was expected to attract over 100 participants, "a gathering of this size is a good cover for possible disruptors". They also noted that the area is frequented by tourists, who could get mixed up in any disturbance.
Jürgen Kasek, regional chairman of the Green Party, called the city's requirements for anti-Pegida protests "outrageous" and added that they "led to the presumption that there is an affinity to Pegida".