The letter arrived ahead of Monday's council meeting, the first since Mayor Rob Ford was stripped of his powers by council. The letter asks councillors to respect the parliamentary tradition of decorum during meetings.
Nunziata's request comes after a raucous November meeting in which Mayor Rob Ford argued with spectators, mimed driving while drunk and bowled over Coun. Pam McConnell.
Shouting from councillors — including Ford's opponents — has become commonplace during council meetings and Nunziata is calling for it to stop.
CBC Toronto city hall reporter Jamie Strashin said Nunziata's letter was prompted by complaints from her colleagues on council.
"She has been approached by a number of members of council who've been dismayed with what they've seen on the floor of council," Strashin reported.
"She says they've gone through an extraordinary set of meetings and has asked councillors to reflect on the rules of decorum that govern them."