The book, first published in 1931, is indeed full of racist clichés. Tintin's creator Hergé distanced himself from it in his later years. The controversial parts have been removed from more recent printings but you can still find them in collectors' editions. Tintin's defenders say the comic books do not contain anything more offensive that what you would find in most literature, and you cannot ban everything. The controversy stems from the fact that the Congolese people were treated brutally by their Belgian colonial rulers. It is still a very sensitive issue in Belgium.