Iran's ILNA news agency named the one person still under detention as a reform-minded former member of parliament, Ali Akbar Moussavi Khoeini.
The Iranian authorities arrested 70 people, including 42 women, at the June 12 protest, saying the gathering was "illegal."
A number of women were beaten when the police moved in to break up the rally, prompting condemnation by human rights groups.
Women In Iran
Women in Tehran (epa file photo)
CALLING FOR MORE RIGHTS: Although women played key roles in Iran's 1979 Islamic Revolution, the place of women in post-revolutionary society has been a vexing question. Iranian women have struggled to bring attention to their calls for greater rights in their country's rigid theocratic system, calls that have often clashed with the values proclaimed by conservatives in society. (more)
For a regular review of civil-society developments throughout RFE/RL's broadcast region, subscribe to "RFE/RL (Un)Civil Societies."