In short. If your child is receiving anonymous texts, you will not be able to identify the sender yourself: neither your carrier nor any app will give you a name. Three things matter: keep the messages without deleting them, block the number or filter withheld calls, then report — to 3018 (harassment of minors), to 33700 (SMS spam) or by filing a complaint. Only a judicial order can trace the sender.
Information verified on 24 October 2026 on the public pages of Arcep, the CNIL, service-public.fr, Légifrance, cybermalveillance.gouv.fr, the 33700 scheme (AF2M), 3018, and on the public support pages of Apple, Google and the French mobile carriers. This article provides general information and is not a substitute for legal advice.
Why does a teenager almost never mention an anonymous text?
Because an anonymous message creates a double fear: fear of the sender, and fear of losing the phone. Many young people stay silent less out of shame than out of calculation: they worry the adult will confiscate the device, read the whole conversation or call the school. The silence protects access to the tool, not the child.
So you have to start by separating two things that always get mixed up:
- the message received, which is a fact and may become evidence;
- the phone, which remains a private space, including for a minor.
On its pages for families, the CNIL points out that the right to privacy also applies to minors, and that parental monitoring must remain proportionate and, as far as possible, explained to the child. Searching the device in secret rarely produces a name and always costs you trust — which is precisely what you will need going forward.
The right way in is a factual question, not an interrogation: "Are you getting messages from a number you don't recognise?" Then: "Do you want us to look together at what we can do?"
Where does an "anonymous" text received by a minor actually come from?
There are four possible origins, and they don't call for the same response. Before taking any steps, work out which one you're looking at: it's the most useful sorting you'll do all day.
| What is displayed | Likely origin | Can you reply? | First action |
|---|---|---|---|
| An unknown 06 or 07 mobile number | A real sender, often someone close or a classmate | Yes | Block, screenshot, do not reply |
| A name in letters (alphanumeric sender) | Professional sending gateway or anonymous SMS website | No, the reply field is often disabled | Screenshot, report to 33700 |
| A 5-digit short code | Commercial service or sending platform | Varies | Report to 33700 |
| "Withheld number" / "Unknown" (call) | Caller ID blocking enabled, or a poorly signalled call from abroad | No | Turn on filtering of withheld calls |
One essential technical point, and a counter-intuitive one for many parents: the #31# code hides your number for a call, not for a text message. A text sent from a French mobile line always carries the originating number. When a text arrives with no usable number, it means it wasn't sent from an ordinary phone but from a sending gateway. We go into this mechanism in detail in our article on the real identity of the sender of an anonymous text.
Put another way: if the message shows an 06 or 07, there is a line behind it, and therefore a subscriber. If the message shows a name or a short code, there is no line to call back — but there is a sending provider, and it keeps logs.
Can you find out who is sending these messages?
No, not by yourself, and no app will do it either. Services promising to "unmask a number" only query public reverse directories or user databases: they see nothing at all when the number is absent from the message header.
What the various parties can do:
- You: read what is displayed, nothing more.
- The carrier (Orange, SFR, Bouygues Telecom, Free Mobile): it holds the traffic data but does not disclose it to a subscriber, not even to the victim's parent. Only the judicial authority can obtain it, by formal request, within the framework set out in the French Postal and Electronic Communications Code.
- The sending platform: it keeps the IP address, timestamp and payment method, and hands them over upon a judicial request.
- The public prosecutor, the investigating judge, the investigators: they alone can follow the chain back.
We have explained the real limits of anonymity in detail in is an anonymous text really untraceable?. Remember the conclusion: anonymity holds up against the recipient, not against the courts.
In practice, for a teenager, the sender very often belongs to their immediate circle: the same school, the same group chat, the same sports team. The content says more than the technology — a message that mentions a nickname, an item of clothing or something that happened the day before points to a very small circle. Note those details down; they will be useful to the investigation.
The five steps, in order
1. Don't reply, don't delete
Replying confirms the number is active and feeds the exchange. Deleting destroys the evidence. The rule is simple: freeze the conversation.
2. Preserve the messages properly
A single isolated screenshot is worth little. You need to capture the whole screen, with the time, the date, the sender's number or name, and the full thread in order. Add a photo of the phone screen taken with a second device: this shows the device itself, not just an image file. A small tabletop smartphone tripod prevents blurry, illegible shots, which are the number one reason evidence gets thrown out.
Keep a written log alongside it — date, time, a summary of the content, your child's reaction. An A5 spiral notebook is enough, and it has the advantage of being dated by hand, page after page. Our dedicated guide explains how to build solid evidence from text messages.
3. Block the number and filter withheld calls
On an iPhone (iOS 18 and later): open the message, tap the name or number at the top, then Info → Block this Caller. For calls: Settings → Apps → Phone → Unknown Callers → Silence.
On Android with Google Messages: long-press the conversation → Block → tick Report as spam. For calls: Phone app → menu → Settings → Blocked numbers → turn on Unknown.
One caveat: blocking does not delete the history already there, but check it first, as some versions hide the conversation.
4. Report it to the right place
- 3018: free national helpline against digital violence targeting minors, open 7 days a week, with an app and a chat service. It is the go-to contact for online and SMS harassment of a young person. It can get content taken down quickly by the platforms.
- 33700: scheme run by AF2M for unwanted texts and calls. You forward the message to 33700, then send the sender's number in a second text. Useful for bulk sends and short codes.
- cybermalveillance.gouv.fr: diagnosis and guidance, including for online harassment.
- The school, if the suspicion points to a classmate: since the law of 2 March 2022, the pHARe programme has been rolled out across all state primary and secondary schools, and every school has a trained support team.
5. File a complaint if the content warrants it
As soon as there are threats, repeated insults, sexual content or pressure, this is no longer a matter for parenting alone. A complaint can be filed at any police station or gendarmerie brigade, or online via the pre-complaint service. Bring the screenshots, the written log, and your child's phone number.
What does French law say when the victim is a minor?
Moral harassment is punished under article 222-33-2-2 of the French Criminal Code, which covers repeated remarks or behaviour resulting in a deterioration of living conditions, with damage to physical or mental health. The text expressly states that the offence is made out even where the perpetrators did not act in concert, provided each of them knew that their messages were adding to others': this is the legal answer to the "raid" in which ten people each send one message.
Penalties are increased where the victim is under fifteen and where the acts are committed through the use of an online public communication service or a digital or electronic medium — which covers text messages.
Two other provisions are frequently used:
- article 222-16 of the Criminal Code, which punishes repeated malicious telephone calls, repeated malicious messages sent by means of electronic communications and noise aggression, with the aim of disturbing another person's peace;
- article 226-4-1, which punishes identity theft, including on a communications network, where someone passes themselves off as a third party in their messages.
A minor who commits these acts is criminally liable from the age of 13 if they are capable of discernment, with a reduction in sentence linked to their minority; below that age, educational measures may be ordered and the parents' civil liability still applies. This is information worth passing on to teenage senders too: "it was just a joke" and "it was anonymous" have no legal value whatsoever.
For the general framework applicable to anonymous sending, see our article is it legal to send an anonymous text in France?.
Should you change your child's number?
Not as a first step. Changing the number cuts off the flow, but it also destroys the continuity of the evidence and simply shifts the problem: if the sender is part of your child's circle, the new number will be doing the rounds within a week. Keep this option for two situations: harassment that persists despite blocking and reporting, or wide circulation of the number on public platforms.
If you do get there, go in this order: complaint first, then preservation of evidence, change of number last — the full process is described in our guide on changing your number without losing everything.
An often more effective alternative: separate the uses. The main number stays reserved for family, school and emergencies; a secondary number, obtained via an eSIM or an app, is used for sign-ups, wider class group chats and apps. A SIM card adapter with ejection tool costs a few euros and avoids risky fiddling when switching over. The principle is set out in our article on the secondary number and dual SIM.
Prevention: three settings and two habits
The settings first. They take ten minutes and sharply reduce the exposure surface.
- Filter unknown senders. On iPhone: Settings → Apps → Messages → Filter Unknown Senders. Messages from numbers not in the contacts list go into a separate tab, with no notification.
- Turn off message previews on the lock screen, so that an aggressive message doesn't pop up in front of the whole class. A privacy screen protector for smartphones is a useful complement to this setting on public transport and in the playground.
- Check the visibility of the number on social networks and messaging apps: most of them let you restrict who can find an account from a phone number.
Then the habits. They matter more than the settings.
Never reply, not even once, not even to say "stop". Any reply turns an isolated message into a conversation, and a conversation into material for a screenshot used against the victim.
And above all: explain to your child that they will not have their phone taken away if they speak up. That is the single most decisive condition for you to find out at the second message rather than the hundredth. On the broader subject of the traces left by a mobile number, our article on the phone number that became a national ID provides useful context.
Finally, for families who want to go back over the basics together: a printed guide to digital parenting, leafed through together at the kitchen table, often achieves more than a long lecture — and it avoids only raising the subject in the middle of a crisis. The reference books published by child protection organisations offer concrete wording, age by age.
Frequently asked questions
Can my carrier tell me who sent an anonymous text to my child?
No. Orange, SFR, Bouygues Telecom and Free Mobile do not disclose traffic data to a subscriber, not even to protect a minor. That data is only released upon a judicial request, as part of an investigation opened after a complaint.
3018 or 33700: which one should I call?
3018 for anything involving harassment or digital violence targeting a minor: it supports the family and can have content taken down. 33700 for bulk unwanted texts and commercial short codes. Both are free and can be contacted in parallel.
Am I allowed to read my teenager's text messages?
Parental authority justifies a degree of vigilance, but the CNIL points out that a minor has a right to privacy. A one-off check, prompted by a serious risk and announced to the child, is defensible; permanent, hidden surveillance is not, and it is counter-productive.
Should I block the number before or after taking the screenshots?
After. Take full screenshots of the thread first, with dates and times visible, then block. On some phones, blocking hides the conversation and makes retrieval harder.
What if the sender is another pupil at the school?
Tell the school: the pHARe programme provides for a support team and a protocol for handling harassment situations. That doesn't rule out filing a complaint if the content includes threats, repeated insults or sexual elements.
Updated on 24 October 2026. Sources consulted: Légifrance (articles 222-16, 222-33-2-2 and 226-4-1 of the Criminal Code), service-public.fr, CNIL, cybermalveillance.gouv.fr, 3018, the 33700 scheme (AF2M), Apple and Google support pages, French Ministry of Education (pHARe programme).
