The brother of jailed Russian opposition figure Alexei Navalny was handed a suspended sentence by a Moscow court on Friday.
Moscow's Preobrazhensky District Court found Oleg Navalny guilty of 'incitement to breach sanitary rules' for calling for street protests in violation of COVID-19 restrictions.
He was given a one-year suspended sentence, with a probationary period of one year.
On Tuesday a senior member of Navalny's Anti-Corruption Organisation, Lyubov Sobol, was sentenced to a year and a half of parole-like restrictions on the same charges as Oleg.
Demonstrations and other mass gatherings have been banned in Russia for much of the pandemic but thousands still took to the streets in April to in a major challenge to President Vladimir Putin's rule.
It came after previous mass protests in the wake of vociferous Kremlin critic Alexei Navalny, 45, being jailed in February.
Navalny was arrested in January shortly after returning from Germany, where he had spent five months recovering after a nerve agent poisoning he blamed on the Kremlin.
In June a Moscow court banned all NGOs and political groups linked to Navalny as 'extremist' amid a deepening crackdown on activists and journalists in Russia.
Last month, the authorities blocked some 50 websites run by Navalny’s team and his supporters for disseminating "propaganda" and asked Twitter to take down Sobol’s account.
The recent wave of shutdowns comes ahead of Russia's September 19 parliamentary election, seen by many as a precursor to next year's presidential election.