Franco, who is not only an actor, but an art student and novelist (amongst other things) has played controversial (and queer) figures before, notably in Howl, in which he played Allen Ginsberg. He also recently directed a film about the life of actor Sal Mineo.
It will be interesting to see what portions of Mapplethorpe’s life they choose to portray, as well as how. Mapplethorpe’s relationship with musician/poet/muse Patti Smith was long and complicated, and Mapplethorpe is perhaps most well-known for his controversial nudes, including a specific self-portrait (link NSFW). Mapplethorpe’s sexuality — and his sexual interests, namely S&M, a culture he documented — are integral to his work, so we shall see how the filmmakers pull this off.
All I know is that I can’t wait to see what they pull out of their asses (pun intended).