What Materazzi said to Zidane (allegedly)

According to Wiki News it was an anti Muslim slur - Zidane is Muslim.

Headbutting incident

He was sent off for violent conduct after headbutting Italy's goalscorer, Marco Materazzi, in the chest in the 110th minute. The game ended in a 1-1 draw and Italy won the championship after a penalty kick shootout.

Both Zidane and Materazzi refused to comment on the incident. Zidane's agent Alain Migliaccio said, "[Zidane] told me Materazzi said something very serious to him but he wouldn't tell me what."[13] Reportedly, the deaf forensic lip-reader Jessica Rees was employed to analyze the video sequences with the help of an Italian translator. According to these reports, Materazzi spoke in Italian - a language understood by Zidane due to his time spent with Juventus F.C. - and first told him: "Hold on, wait, that one's not for a nigger like you." As the players walked forward, Materazzi allegedly said: "We all know you are the son of a terrorist whore." Then, just before the headbutt, he was seen saying: "So just fuck off." [14] [15] According to Brazilian TV Rede Globo, a lip-reader claimed that Materazzi twice called Zidane's sister a prostitute.[16] Earlier claims about Materazzi having called his opponent a "dirty terrorist" have been denied by Materazzi, who reportedly said: "It is absolutely not true, I did not call him a terrorist. I'm ignorant. I don't even know what the word means." [17][13]

On July 10, 2006, Zidane was awarded the Golden Ball for the best player in the 2006 World Cup. The winner was selected in a poll of journalists covering the tournament which began half time of the championship game, prior to the headbutting incident. Zidane won the contest with 2012 points, ahead of second place finisher Fabio Cannavaro, who polled 1977 points. Although the polling continued until midnight, most votes were cast prior to the headbutting incident.[18][19]