Comment by OskarS

I would imagine so. Hergé died in 1983, and the last finished story (Tintin and the Picaros) was published in 1973. I can't imagine its out of copyright.

The first story (Tintin in the Land of the Soviets, a real stinker, this is before Tintin became Tintin) was published in 1930, in Le Petit Vingtième which was the children's edition of the newspaper Le Vingtième Siècle. The newspaper presumably had copyright to the character, but it was shut down in 1940 by the Nazis. After that, Tintin was published in Le Soir (still exists), but I have no idea how the rights transferred. From 1950 onwards, it was published by Hergé's own company.