SEOUL—South Korea approved detailed rules for a law banning dominant app store operators such as Apple Inc. and Alphabet’s Google from forcing software developers to use their payments systems, the country’s telecommunications regulator said on Tuesday. South Korea passed the law, an amendment to the Telecommunication Business Act, last year. It was the first such curb by a major economy on Apple and Google, which face global criticism for requiring the use of proprietary payment systems that charge commissions of up to 30 percent. The rules, called the enforcement ordinance, will be put into effect on March 15. They specify that the law bars “the act of forcing a specific payment method to a provider of mobile content” by unfairly utilising the app market operator’s status, the regulator Korea Communications Commission (KCC) said in a statement. “In order to prevent indirect regulatory avoidance, prohibited acts’ types and standards have been …