The move marks the latest attempt by France to regulate the activities of global internet firms operating in the country and sees ARCEP also launch a probe, in co-operation with public prosecutors, claiming Skype has ignored repeated requests to register.
According to the regulator Skype, which is owned by Microsoft, had an obligation to allow emergency calls and permit legal interception of voicemail traffic whenever required, something it says has not been done.
Skype, however, claims it does not qualify as provider of electronic communications under French law and is therefore exempt.
ARCEP president Jean-Ludovic Silicani said a company is not required to obtain administrative approval to become an electronic communications operator in France, but only to declare itself beforehand under French law.
"A failure to comply with this obligation does, however, constitute a criminal offence," Silicani said: "The fact of engaging in the business of electronic communications operator, and particularly the fact of providing a telephone service to the public, also implies compliance with certain obligations, which include the routing of emergency calls and implementing the means required to perform legally ordered interceptions."
Responding to the investigation Skype said: "We have engaged with ARCEP in discussion over the last several months during which we shared our view that Skype is not a provider of electronic communications services under French law."
European telecoms firms have reported falling mobile bills as users move from voice calls to apps including Skype, What’s App and Viber.
