Song was already automatically suspended for Cameroon's final Group A match against Brazil on Monday.
FIFA says Song will complete his ban in Cameroon's next two official matches. After Cameroon's almost certain World Cup elimination Monday, it plays 2015 Africa Cup of Nations qualifiers in September against Ivory Coast and Congo.
FIFA's disciplinary committee also fined the Barcelona midfielder 20,000 Swiss francs ($22,300).
Song was sent off in the 40th minute when Croatia led 1-0.
- Sports & Recreation
- Alex Song