Its exhibition was forbidden in Brazil in April 1967 for "tarnishing the image of Brazil" but after protests by both Brazilian and French filmmakers, it was authorized by the Brazilian government to be screened at Cannes and in Brazil. What image it is tarnishing is unclear to me, but but every country sees national pride differently.
If any aspect of the film is singled out, it is typically the cinematography. In this case, it comes from Luiz Carlos Barreto, who is more generally known as a prolific producer rather than a cameraman. His best-known film is likely "How Tasty Was My Little Frenchman" (1971). Although he produced 50 films, he only acted as director of photography one other time -- on "Barren Lives" (1963).