Berik Zhaghyparov's lawyer told RFE/RL that her client was sentenced late on May 23.
Zhaghyparov pleaded not guilty, saying he was at the protest as an independent journalist to cover the event.
Police detained Zhaghyparov along with several demonstrators.
The protests began on May 21 when dozens of homeowners from around Kazakhstan demonstrated in front of the government and parliament buildings in Astana.
They demanded the government intervene over what they say are excessive mortgage interest rates and frequent foreclosures.
Two organizers of the protest were sentenced to several days in jail and two demonstrators were fined for their actions.