Racist chants were aimed at Juventus players during the Super Cup at the weekend.
The Curva Nord is the area behind the north goal in Rome's Olympic Stadium.
Lazio lost 4-0 to Juve on Sunday in a rout sparked by a goal from Paul Pogba, a French midfielder.
Spectators had been warned about racist chanting over the stadium loudspeaker during the game.
According to local media the chants were aimed at Pogba, Ghana's midfielder Kwadwo Asamoah and defender Angelo Ogbonna, who were booed by Lazio fans each time they touched the ball late in the second half at Rome's Stadio Olimpico.
A warning was read over the stadium loudspeakers just before the end of the game, although play was not halted.
Italian soccer has been plagued by racist discrimination and it shows no sign of being eradicated despite renewed efforts by the authorities.
In July, a spectator threw bananas at Italy's first black minister Cecile Kyeng during a speech.
Italy's Integration Minister Kyenge has been a target of racist slurs since her appointment in April.
Kyenge, who is originally from Democratic Republic of Congo, appeared at a political rally in Cervia in central Italy on Friday when someone in the audience threw bananas towards the stage, narrowly missing it.
Kyenge has faced almost daily racial slurs and threats since joining the government. Earlier this month a senator from the anti-immigration Northern League party likened her to an orangutan and only apologised after a storm of criticism. – Reuters