In Poe's original 1842 short story, as well as the film, an unknown masked figure appears at a masquerade ball held at the castle home of Prince Prospero. He wears a costume made of bright red fabric, a colour Prospero clearly asked his guests not to wear, and proceeds to spread the devastating "red death" (essentially a fictional version of the Bubonic plague or tuberculosis) amongst the wealthy elite. In the many incarnations of The Phantom of the Opera, the masked Phantom appears at the opera house's masquerade ball donned entirely in red (and his famous mask) during a masquerade ball and demands the company perform the piece he has written for Christine Daaé. "Paper faces on parade," and so on. The moment remains a fabulous scene in every film version I've seen It's a fabulous number and one that I was completely unaware of being inspired by Poe's story.
Though the plague to his doorstep had spread
His own Satanist orgy he'd led
There this skunk who liked watching
Such drunken debauching
Found he hated the horror of red.