UEFA has opened disciplinary proceedings against Roma after a group of supporters allegedly targeted Chelsea defender Antonio Rudiger with racist chants.
The 24-year-old made a £34m move between the two clubs during the summer transfer window, ending his two-year spell at the Stadio Olimpico.
Serie A outfit Roma have now been charged by European football's governing body, with "monkey chants" said to have been made to second-half sub Rudiger during the Champions League clash.
UEFA's control, ethics and disciplinary body will look into the matter further on November 16, two weeks after the sides face off in the return fixture.
Chelsea recovered to earn a 3-3 draw at Stamford Bridge after initially seeing a 2-0 lead overturned by the visitors.