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A scammer has your phone number — what should you do?

Your number is in the hands of scammers? Here are the immediate steps: reporting, blocking, data protection and CNIL procedures.

You have started receiving suspicious SMS messages that know your name, targeted scam calls, or a contact reports being reached by someone impersonating you. These are signs that a scammer has obtained your phone number — and possibly more. This guide explains what to do immediately and how to protect yourself long term.

How scammers obtain your number

The most common cause in 2026 is a data breach at a company you trust — stolen databases are routinely sold on the dark web. Other vectors include scraped public profiles on LinkedIn or classified ad sites, and online forms that legally share contact details with commercial partners.

Signs your number is in the wrong hands

  • SMS or calls referencing your first name or personal details.
  • Contacts receive messages appearing to come from you.
  • You are targeted by multiple different scams in a short period.
  • You receive SMS verification codes for accounts you did not create.

Immediate steps

  • Do not call back any unknown number without first checking it on TelCheck.
  • Alert your carrier if you notice abnormal line activity.
  • Change passwords on all accounts linked to this number — email, banking and France Connect first.
  • Enable two-factor authentication using an authenticator app rather than SMS where possible, to prevent sim-swapping.

Protecting your contacts and reporting

If scams are being sent in your name, warn contacts immediately via an alternative channel and establish a family code word for emergencies. File a complaint with the CNIL (cnil.fr) if a company leaked your data. Report suspicious numbers on TelCheck and on Signal Conso (signalconso.gouv.fr).