I have a ranch home with a two sided fireplace. When I have a fire going, sometimes the basement smells like smoke. (The dampers are open.)
I thought maybe the smoke coming out from the fireplace chimney was being drawn down the furnace's chimney, since they are both right next to each other on the roof. Also does it make a difference if they both have screened chimney caps on them, with the fireplace being lower than the furnace's?