The Italian club were also fined 40,000 euros for a host of offences including displaying an inappropriate banner, igniting fireworks and a late kick-off.
Lazio, whose next European match at their Olympic Stadium in Rome is against Cypriot side Apollon Limassol on November 7, have three days to lodge an appeal after receipt of the written decision.
The sanction is the latest in a string of incidents involving Lazio fans, who have a reputation for extreme right wing politics.
The notorious Curva Nord section of their ground was closed for their Serie A match against Udinese in August after fans racially abused Juventus players during their 4-0 defeat in the Italian Super Cup.
Last season the club was forced to play two home matches behind closed doors in the Europa League after their fans racially insulted Borussia Moenchengladbach players.
There were also violent clashes before their home match against Tottenham Hotspur when home fans engaged in anti-Semitic abuse and fascist salutes because of the English club's historic links to London's Jewish community. ($1 = 0.7355 euros)