This is admittedly a rush job here as I had just an hour before midnight to put up some pictures for the release anniversary of The Fly. A few years ago, I was able to visit some of the locations while in Toronto, check them out below.
First up is the prime location of Seth's loft. Located at 135 Liberty Street near downtown Toronto, the building has gone through some major renovation, but many aspects are still recognizable. The building across from it is about half of what it used to be, but the doors and windows are still the same. (This spot was used in many films including Police Academy and Adventures In Babysitting.)
Monolith Publishing is north of downtown Toronto at 200 Bloor Street East.
The interior was shot at a different building, located at 33 Yonge Street. I didn't go in that bulding, but you can see the mural on the Gooderham flatiron building out the window.
And finally, a quick date scene was shot in the Kensington Market area, in front of 230 Baldwin Street. (This area was used in the last third of Police Academy.)
That is all for now.... be afraid.... be very afraid.