The French telecoms regulator ARCEP said it had asked prosecutors to investigate Microsoft Corp's Skype for failing to register as a telecom operator.

Skype has not complied with the regulator's repeated requests to register as an "electronic communications operator", ARCEP said in a statement on Tuesday.

The regulator said that since Skype let users make voice calls to fixed and mobile numbers in France and around the world, it had an obligation to allow emergency calls and permit legal interception of calls when required.