Last we heard, model and would-be ready-to-wear designer Katoucha Niane had been released from prison in January, after being charged with heroin trafficking in her native Senegal. Well, she’s back in Paris and last week made a surprise appearance at the launch party for Gianfranco FerrA’s autobiography, “Lettres a un Jeune Couturie” (“Letters to a Young Couturier”). She described the drug charges as “a terrible misunderstanding.”