Bina Darabvand took part in protests organised by family members of political prisoners outside the UN building in Tehran calling on the world body to condemn torture being carried out on their relatives.
The judge sentenced Darabvand after concluding that it was illegal for the demonstration to have taken place without prior permission.
Last summer many relatives of political prisoners demonstrated outside the UN building as well as a number of embassies calling for foreign governments to stop negotiations with the clerical state.
A large number of political prisoners throughout Iran went on hunger strike at the time in protest to the Iranian regimes use of torture against its opponents.
