Of course Old City Hall is haunted. It has housed courtrooms since it opened in 1899 and, unfortunately, prisoners used to be executed in its courtyard. Later, hangings took place in the Don Jail. To hint at the spookiness this can conjure, attached is this 1938 watercolour of the Don Jail by Carl Schaeffer (private collection, included in "The Art of Toronto" by Edith G. Firth).
So phantom footsteps have been heard on staircases... Judges' robes have been tugged hard by unseen forces... Clerks have gotten an uncanny blast of cold air in a small, vent-free room between two court rooms... A telephone in the Clerks' office is given to random calls with no one at the other end... A workman quit his job in disgust because "someone" kept moving his tools around, despite co-workers saying that it was probably the work of "the poltergeist". And in 2019, a window in an office door shattered a day after a much-liked judge retired and moved out of that office -- and a CCTV camera recorded that no one was nearby at the time...
There are chilling explanations for why two courtrooms and a long shut-up workroom are said to be haunted. One sensitive visitor has seen a top-hatted, long-coated, "protective, benevolent" male ghost on the 3rd floor. (Might he be associated with buildings which were previously on the site?) In contrast, the same sensitive visitor couldn't go past the original morgue on the 4th floor because of extremely negative energy which she associated with some very bad things that had happened there. More paranormal investigations are needed so that the tour is worthy of ticket prices!