The Number Authentication Mechanism (MAN)

A new operation is requested from all French operators.
This is the MAN for Number Authentication Mechanism.
The objective of this mechanism is to prevent fraudulent and unwanted calls.

To fully understand the issues: we explain

The regulatory context

An interoperable mechanism must be put in place by French operators, in order to comply with the obligation of authentication of the calling number and sender of the message introduced by Law No. 2020-901 aimed at regulating telephone canvassing and combating against fraudulent calls (known as the “Naegelen” law).


This law came into force on July 25, 2023.


The MAN aims to ensure that French voice calls are authenticated and signed when the call is made so that operators terminating the calls can trust them. This obligation concerns all operators providing voice services in France.


The MAN (Number Authentication Mechanism) allows a response to this legal obligation by relying on the STIR (Secure Telephony Identity Revisited) / SHAKEN (Signature based Handling of Asserted information using token) protocols.

The MAN is implemented under the aegis of the APNF in France.

What are the impacts on French operators?

This new legislation requires operators to adapt their operations in order to ultimately secure the use of telephone communications.

Technical compliance

French operators must comply with MAN requirements by implementing number authentication systems. This involves deploying suitable technical infrastructures, carrying out software updates and implementing call management processes in accordance with MAN specifications.

Reduction of telephone fraud

The implementation of MAN allows French operators to fight against telephone fraud by authenticating outgoing call numbers. This helps reduce spam calls, scam calls and number spoofing, thereby increasing user confidence in telecom services.

Judicial services investigations made easier

The MAN mechanism will allow the authorities to investigate more easily by making it easier to trace the origin of a call.

It is obligatory for French operators to comply with the regulations in force and to collaborate with the competent authorities, such as ARCEP or APNF, to implement the MAN in an efficient and secure manner.

By ensuring number authentication, operators can improve user experience and preserve the integrity of electronic communications in France.

The APNF plans to set up an Operator Certificate Base (as provided for by its role as a certification authority), but also a MAN Report Base (BSM). The latter will centralize the traces of calls worthy of being interrupted and of calls actually interrupted, as well as incidents and reports issued by operators.

To better understand: the operation of the MAN in a diagram

Concretely, here is a summary vision of how the MAN works for outgoing and incoming calls on infrastructure

When the Originating Operator receives calls and becomes the Terminating Operator, the same mechanics apply.

Important to note: initially and from July 25, 2023, only unsigned appeals will be canceled. The different ratings will not yet have an impact on an appeal, even if it is rated C, during this first period.

Details on the classification of signatures A, B and C

Classifications Meanings Comments
Sipleo knows the installation and the number presented
Sipleo knows the installation but not the number presented
Sipleo does not know the source of the call (forwarding, international, others, etc.)
Many specific cases involve a C signature. These cases are reported to the APNF so that they can arbitrate to better regulate the signature levels. It is also because of this multitude of cases that calls classified C will not be broken from the start

This classification will above all make it possible to go back to the APNF, through the BSM (MAN Signaling Base), to have numerous metrics to analyze on voice traffic in France.

Questions about the MAN?