The banners caused an outcry after they were displayed by fans on the Curva Sud (south curve) of the Olympic stadium during the Serie A match at home to Napoli on Saturday.
Serie A's disciplinary tribunal said the banners were "by their content provocatively insulting to the mother of a supporter of the opposing team, who died in dramatic circumstances".
The tribunal added that Roma fans were also guilty of discriminatory chanting "against people from a particular territorial origin" and ordered the Curva Sud to be shut for Roma's next home game.
The banners were aimed at Antonella Leardi, the mother of Napoli fan Ciro Esposito, who died last year more than one month after being shot during violent clashes between fans before the Coppa Italia final in Rome.
Although Napoli's opponents in that game were Fiorentina, the incident happened during clashes with Roma supporters.
Leardi has since spearheaded a campaign against soccer violence.
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