The European governing body has confirmed the punishment following a meeting of their control and disciplinary body which took place last week.
City lodged a complaint after Balotelli was subjected to monkey taunts during the first leg of their Europa League last-32 tie at the Estadio do Dragao on February 16.
Porto responded by insisting they were singing in support of their striker Hulk, threatening to file a counter-claim against City for accusing the Brazilian striker of cheating in their chants.
City won the tie but went out to another Portuguese side, Sporting Lisbon, in the next round.
