"It appears, from a 1942 document ... that Hergé gave publishing rights for the books of The Adventures of Tintin to publisher Casterman, so Moulinsart is not the one to decide who can use material from the books." said the Hague court's ruling.
The ruling clarifies that Hergé granted publishing rights for Tintin's books to Casterman in a 1942 document, implying that Moulinsart has no control over how those rights are used.