The book, which was not published in English until 2005, shows the black population bowing down to the boy reporter after he smashes a diamond smuggling racket involving Al Capone.
The black people are depicted as stupid with thick lips. They end up worshipping Tintin and his faithful dog Snowy like gods.
Nick Seaton, secretary of the Campaign for Real Education, said: "As long as children understand times have changed it seems ridiculous to separate this book into the adult section.
"Much of children's literature is extremely graphic and sexually explicit these days and no one seems to bother about that."
He added: "All these silly attempts at censorship do not do a lot of good. Bookshops have to be responsible about things like this but it can go too far and this is ridiculous."
Publisher Egmont UK has put a protective band around the book with a warning about the content. Inside is an introduction by the original translators explaining the historical context.
The warning informs readers Herge's portrayal of the Belgian Congo reflected "the colonial attitudes of the time" and the "stereotypes of the period" which some people "may find offensive".
The restrictions followed a complaint about the book by human rights lawyer David Enright. He said: "It should be in the adult graphic novels section and even then some thought should be given to it.
"There is no way of reading it without thinking it depicts black people as sub human and less mentally able than the apes. They all end up worshipping the dog.
"I always enjoyed Tintin growing up and thought the books were excellent. Then I opened this one up and was shocked to say the least."
The scenes deemed unacceptable:
These are some of the scenes from Tintin In The Congo which have been felt to be inappropriate for today's children include:
*Tintin arrives by train at a mudhut station where thick-lipped Africans are waiting looking puzzled and ridiculously dressed in Western clothes.
*The Africans carry Tintin in a bamboo mounted chair to meet their king, who sits on a wooden throne dressed in a leopard skin, puffing on a pipe and holding a rolling pin as a sceptre.
*Tintin leans casually against a tree as he comes under fire, but the attackersÕ aim is so bad all the arrows and spears bury themselves harmlessly in the trunk, leading to the warriors bowing down to Tintin and declaring he is protected by magical charms.
*Our hero also encounters a tribe of pygmies who have crowned his dog Snowy as their king and placed him on a throne.
*The book concludes with a snapshot of the village where idols of the Ôall powerfulÕ Tintin and Snowy are being worshipped. One villager comments: ÔIn Europe all young white men is like Tinti