If you go to the Tower Bazaar back behind where Hawthorne is underneath that structure with the orange cloth roof you will find a treasure chest. It doesn’t seem to give you anything though. If you leave the area and come back it will give you the option to collect loot again.
It you stand just to the right of that next to the corner of the gated door it will say, “Requires Dance Party Key”. Go to the basement below and on top the final set of stairs it will say the same thing.