What to do after giving sensitive information over the phone

Giving sensitive information to a fraudster is not inevitable: between the moment the information is communicated and the moment it is used, several minutes to several days often pass. Every action in this window counts. Opposition, change of password, dispute: the steps are simple, free, and all the more effective the sooner they are done. And above all: there is nothing shameful about having been deceived by manipulation professionals — tens of thousands of French people report it every year.

Actions to take, hour by hour

1. 1
   Within the hour — call your bank

   If the information directly or indirectly affects your means of payment (card, SMS code, online banking identifiers, IBAN), call your bank at the number on the back of your card or on your statements — never a number given by the caller. Outside branch hours, the interbank opposition server responds 7 days a week to 0 892 705 705. Explain precisely what has been communicated: the bank will block what needs to be blocked.

2. 2
   Within the hour — change affected passwords

   If you have given a password (or if a stranger has gained access to your computer), change it immediately, from a secure device. Start with messaging: this is what resets all the other accounts. If the same password is used elsewhere, change it everywhere.

3. 3
   Same day — check your accounts and pending transactions

   Review the latest movements in your accounts and pending transactions: unknown payments, scheduled transfers, new beneficiaries added, enrolling your card in a mobile wallet. Report each anomaly to your bank and request a written dispute.

4. 4
   In the days that follow — complaint and reports

   File a complaint with the police or gendarmerie (or via the teleservice Percival for card fraud). Report the fraudulent number to 33700 and the attempt on cybermalveillance.gouv.fr. Keep everything: call times, displayed number, screenshots, records.

5. 5
   The following weeks — stay alert, the file is circulating

   A person who responds once becomes a marked target: your number and information circulate between fraud networks. Expect calls from "your bank", "victim reimbursement service" or other customer services. Monitor your statements (you have 13 months to dispute an unauthorized withdrawal) and never validate a transaction requested by telephone.

What each piece of information risks – and the solution

Not all information has the same gravity. Here is what each piece of data allows a fraudster, and the corresponding priority action.

• Card number + date + cryptogram: Immediate online payments possible. Priority action: immediate opposition, without waiting for the first debit.

• Code received by SMS: he probably validated a specific transaction - payment, transfer, or registration of your card on the fraudster's phone. Priority action: call to the bank to identify and cancel the validated transaction.

• Online banking identifiers: consultation of accounts, addition of beneficiaries, transfers. Priority action: change of password and verification of registered beneficiaries, with the bank on the telephone.

• IBAN: setting up fraudulent direct debits. Priority action: monitoring of statements and immediate dispute — an unauthorized withdrawal can be disputed up to 13 months after the debit.

• Personal data (name, address, date of birth, situation): no direct loss, but they make the next scam credible - notably the fake bank advisor. Priority action: warn your loved ones and be extra vigilant about incoming calls.

Numbers and services to know

1. Bank card opposition (interbank): 0 892 705 705 — 7 days a week, 24 hours a day, if you cannot reach your bank.
2. Scam Info: 0 805 805 817 — free, Monday to Friday, for advice from specialized police officers.
3. 33700 — reporting fraudulent telephone numbers and SMS messages.
4. Cybermalveillance.gouv.fr — diagnosis, reflex sheets and official assistance to victims.
5. Percival (service-public.fr) — online reporting of bank card fraud, when you still have your card.

Preventing the next call: the role of Kin-Guard

After a first incident, the main risk is the callback: fraudsters return to people who have already responded, often pretending to be the bank or a victim support service. This is exactly the channel that Kin-Guard closes: calls from unknown numbers are handled by the assistant, which verifies identity and reason before transmitting — and blocks known fraud scenarios. The protected person is never alone again with a stranger on the phone.

Frequently asked questions

Article written by Charlie BART, founder of Kin-Guard. Published on July 7, 2026.

Sources: Service-public.fr — Scam and bank fraud · Cybermalveillance.gouv.fr · OSMP — Bank of France

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