France Postal Validator

French postal code (code postal): five digits keyed on the département

The French code postal is a 5-digit number where the first two digits identify the département and the remaining three narrow it to a commune or delivery zone. Introduced by La Poste in 1964 and generalised in 1972, it replaced the older two-digit département codes. The validator on this page checks the structural format — exactly five digits — accepting 75001 (Paris 1st arrondissement) or 13002 (Marseille).

There is no check digit: a code is valid if it exists in La Poste's Base officielle des codes postaux, an open dataset mapping each code to its INSEE commune code and place name. Unlike many countries, a single French commune can share its code with neighbours, and large cities split into several codes by arrondissement.

Reading the first two digits

• 01–95: metropolitan départements (e.g. 75 Paris, 13 Bouches-du-Rhône, 69 Rhône, 33 Gironde).
• 20: Corsica in postal codes — even though the administrative codes are 2A (Corse-du-Sud) and 2B (Haute-Corse), the postal code keeps 20xxx.
• 97 / 98: overseas départements and territories (971 Guadeloupe, 972 Martinique, 973 Guyane, 974 Réunion, 976 Mayotte, 987 Polynesia, 988 New Caledonia).
• Trailing 0s: codes ending in 000 are usually the préfecture / main town of the département.

Where it shows up

• Address forms: code postal + ville is the canonical French address line; many forms auto-fill the commune from the code.
• CEDEX: business mail uses a Courrier d'Entreprise à Distribution EXceptionnelle code (e.g. 75008 PARIS CEDEX 08) for high-volume recipients.
• Stats & elections: pairs with the INSEE code for demographic and electoral data.
• Mock data / testing: generating valid-format codes for fixtures and address QA.

Gotchas

• Code postal ≠ INSEE code: the postal code is for La Poste routing; the INSEE code uniquely identifies the commune for statistics. They differ.
• One code, many communes: a rural code can cover several villages; don't assume a 1:1 mapping to a town.
• Corsica trap: postal code is 20xxx, administrative code is 2A/2B — mixing them breaks lookups.
• Format-valid ≠ real: 99999 passes the regex but isn't in the official base.

FAQ

Do the first two digits always equal the département number? Almost always, with the Corsica (20) and overseas (97/98) exceptions noted above.

What is a CEDEX code? A special distribution code for businesses and institutions that receive large volumes of mail, delivered through a dedicated channel rather than the normal round.

Is there a check digit? No. Validity is by lookup against La Poste's official code base, not arithmetic.