The Supreme Court reversed a lower court decision and said in a ruling published Wednesday that anti-police, anti-Spain discrimination hadn't taken place so shouldn't factor into the length of prison sentences.
The seven men and one woman originally received sentences of 2 to 13 years. The Supreme Court reduced them to between 1½ and 9½ years, saying the assault victims suffered physical and psychological damage in the bar brawl.
The eight can appeal to Spain's Constitutional Court.
This story has been corrected to show the crime happened in 2015, not 2016.