School SMS Sender ID France: The 2026 Rules and the Fix

Since 1 March 2026, the name your school displays on parent SMS is a validated technical field, not a label. Under the af2m Business Messaging Charter, the SMS sender ID a French school shows on parent messages must be at most 11 Latin alphanumeric characters — no accents, spaces, hyphens or punctuation — must not be all digits, and must not be a generic word such as “Alerte”. af2m publishes the rule; operators and aggregators state that a sender failing it is overwritten or blocked at transmission.

So a sender reading Collège J. Moulin fails on four counts at once — length, an accented character, spaces and punctuation — and ALERTE fails even though it is short and clean.

Expéditeur SMS règles 2026: the sender-name test to run now

• Length — 11 characters maximum, no exceptions to the limit. [af2m; I SEE U]
• Character class — digits 0-9 and unaccented Latin letters A-Z only. Special characters, accented characters, spaces, punctuation and non-Latin alphabets are all prohibited. [LINK Mobility]
• Not all digits — a sender made only of numbers is rejected because it resembles a phone number. [smsmode; LINK Mobility; I SEE U]
• Not generic — “alert”, “appointment”, “payment”, “bank” and “delivery” are blocked as standalone senders; “Alerte” and “Rappel” are named as misleading generic terms. [smsmode; I SEE U]
• Not a protected name — names in the SI (“Strictement Interdit”) category such as ANTAI, AMELI, GOUV and SECU are blocked outright; names in the ISA category (“Interdit Sauf Autorisation”) need documented written authorisation. [af2m; smsmode]
• Identifies you — the sender must clearly identify the entity behind the message. [af2m; LINK Mobility]

Format examples from vendor documentation make the line easy to see: Mon Entreprise is invalid (space, over 11 characters), Boutique! is invalid (special character), MONENTREPRI is valid. [I SEE U]

School SMS sender ID France: what changed, and on what date

The charter was published on 13 February 2026 and came into force on 1 March 2026, according to af2m itself. LINK Mobility gives the same date and adds the detail that matters most to schools using a non-French platform: the rules apply to all SMS traffic routed to French mobile networks regardless of the country of origin. Buying from a cheaper foreign gateway does not put you outside the charter.

One date circulating in vendor communications needs care. The 1 May 2026 “hard cut-off”, after which non-compliant senders are blocked, comes from I SEE U — a single vendor blog asserting a date that af2m’s own pages do not carry. Neither af2m page consulted for this article mentions it. Treat 1 March 2026 as the date the obligation started and 1 May 2026 as a date to check with your own provider — either way, both are behind you as you plan the rentrée.

The declaration procedure runs through af2m’s Extranet, effective March 2026, with a working group examining contested declarations. Once a status lands on a name, a clock starts for the operators’ contracted partners — the platform or aggregator sending your traffic: 2 business days to stop using an SI sender, 30 days to obtain and document authorisation for an ISA sender. Your provider is on that clock, and will come to you inside it. [af2m]

Why a “valid” 11-character name still gets overwritten

The failure mode schools should worry about is not a bounce. smsmode documents that a non-compliant sender “may be overwritten or blocked by smsmode or subsequent telecom operators”, and that the platform will overwrite special characters during transmission. An overwrite is not a bounce: the message still leaves, and what the parent sees is a sender name other than the one you configured. A nom expéditeur SMS of 11 caractères that passes your platform’s own field validation can still arrive under someone else’s label.

Nor does provider acceptance settle it. SFR Business documents blocking SI senders at transmission on its own network and requiring prior approval plus brand registration before an ISA sender can run in a campaign. Enforcement sits at the operator, not only at the sending platform, and af2m makes every actor in the delivery chain responsible for its own compliance and its co-contractants’ — with interruption of delivery as the sanction. af2m’s OADC page also publishes no list of protected sender names, so a school cannot self-check a candidate name against a public register; it has to go through its provider or af2m. [af2m]

Logiciel SMS école: four routes, compared

Fixing the field is a five-minute job. Deciding who owns the field from now on is the procurement question.

Route	Who controls the sender name	Compliance work the school owns
Direct A2P aggregator contract — LINK Mobility, smsmode, SMS Partner	The school, working through the platform’s declaration and verification route	Sender declaration, ISA authorisation letters, opt-in records, STOP handling
Operator business SMS platform — SFR Business DMC	The school, with operator pre-approval and brand registration for ISA names	The same, plus operator-side approval before a campaign runs
Existing vie scolaire / school-management platform	The publisher	Verify the declared sender with the publisher; confirm whether your establishment name or the publisher’s appears on the handset
School communication platform with a built-in SMS module	The platform provider	Recipient list hygiene, opt-in capture, choosing the right message category

Two of those column-three entries are category labels rather than practices, so here is what they look like in a secretariat.

STOP handling, concretely. A STOP arriving at 21:10 on a Friday must remove that number from the promotional list before the next send, with the removal timestamped in your register. On an aggregator contract you configure and test that yourself; on a school platform you check a box.

Opt-in capture, concretely. One tick-box on the enrolment dossier reading j’accepte de recevoir les informations de l’établissement par SMS, stored with the dossier validation date, so that a challenged promotional send can be traced to a dated consent — as distinct from the absence alert, which needs no consent because it is transactional.

The exact commercial shape of each route — per-message credits, platform fees, bundling into a telecom contract or into an existing subscription — varies by supplier and is not something the charter or the operator documentation sets.

SMS établissement scolaire: what the cost actually turns on

Per-message price is the number schools compare and the least useful one. Three other lines move the total more:

Contract overhead. A standalone aggregator contract is a second supplier, a second DPA, a second set of credentials and a second renewal to negotiate — for a service typically used in bursts around absences, closures and enrolment.

The declaration burden. Every sender name in your name is a name that must be declared, defended if it is contested, and re-documented if an ISA status lands on it — inside the 30-day window the charter gives the partner sending your traffic.

The cost of a silent failure. A blocked or overwritten absence alert would likely mean a phone round by your secretariat the next morning. That labour never appears on the SMS invoice.

Because no public source sets the price, make each supplier put the same five lines on the quote:

1. Unit price at 5,000 messages a year and at 20,000 — the two ends of a single établissement’s realistic volume.
2. Whether sender declaration and ISA authorisation are billed as a service or included.
3. Whether unused credits expire at year end.
4. Whether a separate DPA is required, or the SMS traffic sits under an existing one.
5. Who is named as the operator’s co-contractant — that is the party carrying the 2-business-day and 30-day clocks.

Verdict: the route that removes the most recurring work is the one where the sender name is declared once by the provider and school staff never touch the OADC field again.

What else stops the message arriving

The sender name is not the only thing that changed, and a compliant name does not guarantee reach. Envoi SMS parents élèves has two more gates after the sender field: consent and timing.

The charter also requires prior opt-in for promotional messages — with a single opt-in now covering both SMS and RCS — unsubscribe via STOP keyword, dedicated URL or RCS action button processed immediately with no payment or added complexity, and a promotional sending window of 08:00 to 21:30, Monday to Saturday recommended. Transactional messages remain unrestricted, which is the distinction that lets an absence alert leave at 07:40. [af2m; SMS Partner]

In practice that split sorts almost every message a school sends:

Message	Category	What the charter imposes
Absence alert, 07:42	Transactional	No window, no opt-in needed
Closure for snow, 06:15	Transactional	No window, no opt-in needed
Kermesse reminder	Promotional	08:00–21:30, Mon–Sat, opt-in list only, STOP line required

Not the same file. A second, legally separate track is running alongside the charter. Number-spoofing reports to Arcep rose from 531 in 2023 to more than 19,000 in 2025 — the primary cause of complaints submitted to the regulator. Under the July 2020 law, operators must authenticate the calling number and cut off calls where the number is not properly authenticated, with progressive rollout from October 2024; since 1 January 2026 they must mask any French mobile number that could not be authenticated during calls from abroad, and Arcep opened an administrative enquiry into all operators holding French numbering-plan numbers on 29 January 2026. This is a call and number-authentication regime, not an SMS sender rule — but if your school’s outbound calls started showing as masked, that is the file to read, not the charter.

Before you blame the sender name

Nothing in the public record measures how many school SMS actually fail, or why: the charter, the operator pages and the aggregator documentation describe rule and platform behaviour, not observed school deliverability. If your reach has dropped, the sender name is one plausible cause among several. Missing or unrecorded opt-in, STOP requests that were never processed, promotional sends outside the permitted window, and simply stale parent mobile numbers collected years earlier are each capable of reducing reach, and nothing in the sources lets you tell them apart from the outside. Channel substitution matters too — if messages already route through your vie scolaire platform or a multi-channel announcements tool, the sender name is declared by its publisher rather than by you. Diagnose before you re-procure.

The fix, in order

1. Test and replace the sender name this week. (20 minutes, secretariat.) In practice, this looks like opening the sender field in your SMS platform, replacing Collège J. Moulin with COLJMOULIN — 10 characters, unaccented letters only, still recognisable — then sending one test SMS to two staff mobiles on different networks with the body Test expediteur - ne pas repondre, and reading the name that arrived on the handset rather than the name in the send log.

2. Separate transactional from promotional in your sending rules. (One afternoon, whoever owns the sending rules.) In practice, this looks like an absence alert firing automatically at 07:42 with the body Absence non justifiee de votre enfant ce matin. Merci de rappeler le secretariat au 01 XX XX XX XX. — unrestricted as a transactional message — while the fête de l’école reminder is queued to a single send at 17:00 on a weekday, once per event, carrying a STOP line and going only to families who opted in.

3. Open a sender file before your provider asks for one. (One page, kept with the RGPD register.) In practice, this looks like one page per sender name: the exact OADC string, the date it was declared to your provider, the af2m Extranet reference, the written authorisation scan if the name carries a partner’s brand, and a review checkbox ticked each rentrée — so that when a 2-business-day SI notice or a 30-day ISA notice reaches your provider, the paperwork it needs from you already exists.

4. Clean the numbers at enrolment, not at the alert. (A change to the enrolment form, next dossier cycle.) In practice, this looks like a mandatory mobile-number field with a French-format check on the enrolment form, a confirmation SMS sent once a family’s dossier is validated, and a periodic export of numbers that returned no delivery receipt, handed back to the secretariat as a call list.

What this means for your next rentrée

The obligation is not pending, it is live: the charter has applied to every message reaching a French mobile since 1 March 2026, and the only variable left is whether your establishment fixes its sender field before or after a parent misses an alert. Getting there means a sender name that survives operator validation, a clean split between transactional and promotional traffic, opt-in and STOP records you can produce on request, and a declaration file per name. Purpose-built school communication platforms can hold that layer so the secretariat never touches an OADC field — BeeNet’s SMS module is one implementation path; book a walkthrough if you want to see how the sender declaration is handled end to end. Whichever route you take, do it this term — the next absence alert is the one that has to arrive.

References

1. af2m. Charte Business Messaging 2026 : l’af2m renforce les règles du jeu. Published 13 February 2026, in force 1 March 2026. https://af2m.org/charte-business-messaging-2026-laf2m-renforce-les-regles-du-jeu/
2. af2m. Protection des OADC sensibles. Declaration procedure effective March 2026. https://af2m.org/protection-des-oadc-sensibles/
3. LINK Mobility France. Nouvelle réglementation sur les expéditeurs SMS en France. 2026. https://www.linkmobility.com/fr/news/nouvelle-reglementation-sur-les-expediteurs-sms-en-france
4. SFR Business. DMC — OADC sensibles et interdits. Assistance Relation Client product documentation. https://assistance.utilisateur-relationclient.sfrbusiness.fr/dmc/dmc-oadc-sensibles-et-interdits/
5. smsmode. SenderID and OADC compliance in France. Knowledge Base. https://support.smsmode.com/en/base-de-connaissance/conformit%C3%A9-des-senderid-ou-oadc-en-france
6. I SEE U. Réglementation SMS 2026 : nouvelles règles au 1er mai. 2026. https://isee-u.fr/blog/reglementation-af2m-expediteur-sms-2026/
7. SMS Partner. Charte Business Messaging 2026 : ce qui est désormais autorisé (ou strictement interdit). 2026. https://www.smspartner.fr/blog/charte-business-messaging-2026/
8. Arcep. Protection des consommateurs : l’Arcep ouvre une enquête administrative sur l’usurpation de numéros. Press release, 29 January 2026. https://www.arcep.fr/actualites/actualites-et-communiques/detail/n/protection-des-consommateurs-290126.html