World soccer's governing body said disciplinary proceedings had been opened against Mexico for "improper conduct" during their 1-0 win over the African side in Group A.
Mexico fans have long shouted an insult at keepers taking goalkicks, which some gay rights groups argue is homophobic.
FARE, an anti-discrimination campaign group, said it had contacted FIFA about four incidents of racist or homophobic behaviour at the World Cup, including the chants at the game between Mexico and Cameroon.
A FIFA spokeswoman said no other disciplinary proceedings had been launched at this point.
Piara Powar, executive director of FARE, said the group had told FIFA about banners showing far-right symbols or messages held by fans of Croatia and Russia at World Cup games in Brazil.
Powar said the fourth incident related to the same chants by Mexico fans at the country's second match against hosts Brazil, and which some home team fans copied.
"This is something that we really felt we needed to draw to the attention of FIFA," he said.
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