The 57-nation Organisation of Islamic Cooperation's human rights body accused Charlie Hebdo of "ridiculing the most revered personality" of Islam but urged the world's more than 1.5 billion Muslims "to continue to exercise restraint".
The appeal came after thousands around the world demonstrated against a new cartoon published by the French weekly last week.
The worst unrest has been in the African nation of Niger, where 10 people were killed and at least eight churches torched.
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The new cartoon is an "intolerant, disrespectful and manifest expression of hatred as well as insensitivity" toward Muslims, said the OIC's Independent Permanent Human Rights Commission, an expert advisory body established by the Saudi-based Muslim bloc.
The commission had earlier condemned the "barbaric" January 7 attack on the Paris office of Charlie Hebdo which left 12 people dead.
The attackers, brothers Cherif and Said Kouachi, were later shot dead by police.
The brothers said they were taking revenge for previous Mohammed cartoons published by the magazine and considered deeply offensive by many Muslims.