The demonstration on July 30, organized by the civic group Democracy, called on Western countries to continue promoting human rights in Kyrgyzstan.
Police confiscated banners and flags from participants and detained protest leader Tursun Islam, who was released later the same day.
Islam's son, Alisher, told RFE/RL's Kyrgyz Service that he was also jailed and spent three days in custody.
The human-rights bodies said the incident follows other cases in Kyrgyzstan in which human rights defenders have been "subject to pressure and the threat of criminal prosecution." They called on the Kyrgyz authorities to ensure that legitimate and peaceful protests can take place freely and without repercussions for the participants.