Thousands of people gathered in Moscow and other cities Thursday night after Navalny was sentenced to five years in jail for embezzlement, RIA Novosti said.
The trial was internationally condemned as Russia's retaliation for Navalny's role in rallies against Vladimir Putin last year.
Protesters covered the walls and doors of the Russian Parliament with stickers that said "Change Russia. Start from Moscow" with Navalny's name and face on them.
Others left graffiti that denounced Putin.
Police said in a statement that the unidentified protesters who sprayed the graffiti and left the stickers will be charged with vandalism, and face fines and jail time.
RIA Novosti said Navalny was released Friday, pending appeal. He said Thursday's protests contributed to his release.