The eight defendants were found guilty of participating in mass riots and hitting policemen at an opposition rally the day before Putin returned to the Kremlin for a third term in 2012.
The guilty verdict came during the showpiece Winter Olympic Games in Sochi, which Putin helped bring to Russia for the first time.
Around 1,000 supporters of the activists gathered outside the Zamoskvoretsky district court ahead of the ruling.
Around 200 people were detained over several hours, a spokesman for Moscow police said. An AFP correspondent saw dozens being detained and put in police vans for shouting or even just carrying balloons.
Opposition figures such as protest leader Alexei Navalny and two recently released members of protest punk band Pussy Riot, Nadezhda Tolokonnikova and Maria Alyokhina, came to the trial and stood on the street after being denied entry.
Prosecutors have asked for prison sentences of up to six years for the eight defendants, terms called disproportionately harsh by the defence team and human rights organisations.
The trial was adjourned and the sentencing was scheduled to continue on Monday -- one day after the Winter Olympic Games close.
