Unauthorised sequels

There was a copyright case in France recently, Pierre Hugo and others v SA Plon and another (Cour d'appel de Paris), on whether Victor Hugo's moral rights were breached by the publication of a couple of unauthorised sequels to Les Miserables.

Even though the specific legal issues were different it reminds me of the case over The Wind Done Gone, when Margaret Mitchell's estate sued Alice Randall and her publishers over the publication of her first novel, a parody of Gone with the Wind, written from the perspective of Scarlett O'Hara's half-sister Cynara, a slave on Scarlett's plantation. The estate managed to get an injunction preventing the publication initially but the case was eventually settled out of court and the book was published in 2002.