When we receive a call from a number starting with 04 12, we hesitate to answer, wondering if it’s a salesperson or a tradesperson calling back for a quote. This reflex sums up the daily life of the French in response to telephone area codes. The prefix 04, and more specifically the range 04 12, corresponds to a specific geographical area in the southeast of France, linked to the national numbering plan.
Before detailing the covered areas and uses, one point deserves attention: the ability to identify a number in 04 12 helps to filter calls and spot attempts at abusive solicitation.
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Telemarketing and numbers starting with 04: prefixes to watch out for
Since 2023, ARCEP and the government have required call centers to use dedicated prefixes for telemarketing, notably the blocks 0424 and 0425 in metropolitan France. When we see an incoming call starting with these numbers, we immediately know what to expect.
This measure changes the game on a daily basis. Instead of answering blindly, we can configure our phone to block these ranges or simply ignore the call. Feedback varies on this point, as some legitimate professionals based in the southeast also use similar numbers, but the rule remains reliable for individuals.
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To learn everything about the 04 12 area code in France, it is also important to understand the time constraints that now frame these commercial calls.
Since March 1, 2023, telemarketing is prohibited on weekends and limited to the hours of 10 AM to 1 PM and 2 PM to 8 PM from Monday to Friday. The same offer can only result in a maximum of 4 calls per month to the same number. These rules apply to all area codes, including numbers starting with 04.
04 12 area code and geographical coverage in the southeast
The prefix 04 covers the entire southeast of France. It includes three major administrative regions:
- Auvergne-Rhône-Alpes, with departments such as Rhône, Isère, Savoie, Haute-Savoie, Loire, Drôme, or Ardèche
- Provence-Alpes-Côte d’Azur, including Bouches-du-Rhône, Var, Alpes-Maritimes, Vaucluse, and Alpes-de-Haute-Provence
- Corsica, linked to the same area code despite its insularity
The range 04 12 corresponds to a sub-block assigned by ARCEP to operators distributing these numbers in this area. A number in 04 12 can therefore be located in Lyon, Clermont-Ferrand, or in a rural municipality in Cantal.
The area code does not guarantee the physical location of the caller. With VoIP, a company based in Paris can use a number in 04 12 to display a local presence in the southeast. This is a common and perfectly legal practice.
International format and calls from abroad to a 04 12 number
When calling a number in 04 12 from abroad, you replace the initial zero with the international dialing code for France. The number 04 12 XX XX XX thus becomes +33 4 12 XX XX XX.
This conversion applies to all French landline numbers. The +33 (or 0033) systematically replaces the first zero. For a call from a mobile registered abroad, the +33 4 format works without any additional manipulation on almost all networks.
A practical point often overlooked: if you save your French contacts directly in the international format (+33 4 12…), the number remains reachable whether you are in France or abroad, without having to modify anything in your directory.
Cost of a call to a fixed number starting with 04
Numbers starting with 04 are non-premium numbers. They are included in the fixed and mobile national plans offered by French operators (Orange, SFR, Bouygues Telecom, Free). From abroad, the cost depends on the international plan subscribed, but the number itself does not generate any premium charges.
Mandatory opt-in in 2026: what will change for calls to 04 numbers
A new law adopted in May 2025 profoundly changes the framework for telemarketing. Starting in August 2026, companies will no longer be able to contact individuals, including via numbers starting with 04, without obtaining explicit prior consent.
This shift from opt-out (registration on Bloctel to refuse calls) to opt-in (agreement given before any call) represents a complete change in logic. In practice, if nothing has been signed or checked, we should no longer receive commercial calls.
For professionals in the southeast using a number in 04 12 for their business activity, this evolution requires a review of their prospecting methods. The number in 04 retains its value of local proximity, but its use for cold calling becomes nearly impossible without documented consent.
French numbering plan: where does 04 fit among other area codes
The French telephone system is based on a geographical division by prefix for landlines:
- 01 for Île-de-France
- 02 for the northwest
- 03 for the northeast
- 04 for the southeast
- 05 for the southwest
Prefixes 06 and 07 are reserved for mobiles. The 08 prefixes correspond to special numbers (free, premium-rate, or standardized). The 09 prefixes are assigned to VoIP lines, such as internet boxes.
This division dates back to the numbering plan implemented in the 1990s. It remains the basis of the current system, even though VoIP has blurred the strict correspondence between area code and actual location.
The prefix 04 12, like all ranges of block 04, remains a reliable marker for identifying a call from the fixed network in the southeast. With the new rules on telemarketing and the shift to opt-in expected in August 2026, reading the first digits of an incoming number is becoming an increasingly useful reflex in daily life.