New changes to numbering rules expected in France

The ARCEP is considering a new modification to the national numbering plan. This project, which continues the successive adjustments made since 2018, aims to modernize the framework for the allocation and use of numbering resources, while incorporating new provisions from the law of 30 June 2025 against all public aid fraud.

Operators – or any interested party – are invited to submit their feedback before 26 September 2025, and are especially encouraged to respond to the 26 questions posed by ARCEP.

ARCEP is planning to adopt the following measures:

•    A strengthening of measures against caller ID spoofing

ARCEP is considering a set of measures to reinforce the fight against caller ID spoofing, a phenomenon that has been on the rise despite the authentication system introduced by the law of 24 July 2020. Since January 2025, more than 10,000 reports have been recorded on the "J’alerte l’Arcep" platform, showing that the existing mechanisms are being bypassed by those making fraudulent calls.

In light of this, ARCEP proposes to take action on three levels:

1.    Displaying the generic number "99 99 99 99 99" for unauthenticated calls using a French mobile number from abroad: A large number of fraudulent calls, made from abroad with spoofed mobile numbers, reach France without being blocked. French operators are unable to distinguish these from legitimate roaming calls made by French subscribers. To reduce the risk of spoofing while ensuring communication continuity, ARCEP proposes that, in such cases, operators should replace the caller's number with the generic fixed number "99 99 99 99 99," indicating that the displayed number is unauthenticated.

2.    A recommendation for operators to display the generic number when, for technical reasons, they cannot transmit caller authentication information: Sometimes, technical vulnerabilities prevent operators from obtaining authentication information for the caller's number.
ARCEP recommends that in such cases, the caller's number should also be replaced with the generic fixed number "99 99 99 99 99" to limit fraudulent risks without blocking potentially legitimate calls.

3.    A clarification of the obligations for originating operators regarding prior verification of caller numbers used by their clients: ARCEP wants to clarify contractual obligations for operators towards their clients by requiring contracts to specify the list of numbers that the client is authorized to use, and technically restrict use to this list. This measure aims to prevent any unauthorized use of caller numbers as soon as the call is initiated.

• Creation of a new number category for calls and messages serving a public interest

Pursuant to Article 16 of the law of 30 June 2025 on combating all public aid fraud, ARCEP plans to introduce a new category of numbers for automated calls and messages carried out in the context of a public interest objective. These numbers can only be allocated to entities specifically designated by a joint decree of the ministers responsible for consumer affairs and electronic communications.

• New number management measures in Overseas territories to prevent shortages and meet growing business demand

Faced with a significant increase in number requests in the Overseas territories, certain resources allocated in the numbering plan for various overseas regions are becoming insufficient to meet the needs of companies and operators. To address this, ARCEP proposes measures to improve the efficiency of number management and plans to allocate new ranges to anticipate potential shortages.

• Additional measures:

ARCEP is considering several updates to the national numbering plan to strengthen consumer protection, responding to operator requests and reports submitted via the "J’alerte l’Arcep" platform.

1.    A ban on displaying heavily surcharged short numbers as caller IDs, to prevent misleading practices;

2.    A temporary freeze on disconnected numbers, especially in the case of technical closure of access, such as following the technical closure of copper network access, allowing the affected user to request retrieval of their number before it is reassigned.

The document is open for public consultation until 26 September 2025 at 6:00 p.m. and can be accessed here.
These changes will be finalized, with possible modifications taking into account operators' responses, in the coming months.