French Postal Code Enrichment, Commune, GPS, and Regional Data

More than just a city name

A French postal code maps to one or more communes, each with its own administrative hierarchy. The API returns the full picture:

import httpx

response = httpx.get(
    "https://frenchbusinessapi.com/postal/code/75008",
    headers={"X-API-Key": "your_api_key"}
)
data = response.json()
for commune in data["communes"]:
    print(f"{commune['nom']}, {commune['departement']}, {commune['region']}")
    print(f"  GPS: {commune['latitude']}, {commune['longitude']}")

For Paris (75008), you get the arrondissement, département (Paris), région (Île-de-France), and precise GPS coordinates.

One postal code, multiple communes

Outside major cities, a single postal code often covers several communes. The code 01000 covers both Bourg-en-Bresse and several smaller communes. The API returns all of them:

response = httpx.get(
    "https://frenchbusinessapi.com/postal/code/01000",
    headers={"X-API-Key": "your_api_key"}
)
print(f"{len(response.json()['communes'])} communes for postal code 01000")

This is essential for address forms: when the user types a postal code, you can show a dropdown of communes to select from.

Reverse lookup: commune to postal code

Search by commune name to find the postal code:

response = httpx.get(
    "https://frenchbusinessapi.com/postal/search",
    params={"q": "Marseille", "limit": 5},
    headers={"X-API-Key": "your_api_key"}
)
for result in response.json()["results"]:
    print(f"{result['code_postal']}, {result['nom']}")

The search is fuzzy: "Marseile" (one L) still finds Marseille. Accented and non-accented queries both work.

Use cases

Smart address forms

Build a checkout or registration form that auto-completes:

1. User types a postal code

2. API returns matching communes

3. User selects their commune from a dropdown

4. Département, région, and GPS are auto-filled

This reduces errors and speeds up checkout, critical for e-commerce conversion.

Delivery zone calculation

Use GPS coordinates to calculate delivery zones and shipping costs:

# Get coordinates for two postal codes
origin = httpx.get("https://frenchbusinessapi.com/postal/code/75001", headers=HEADERS).json()
dest = httpx.get("https://frenchbusinessapi.com/postal/code/13001", headers=HEADERS).json()

# Calculate approximate distance
from math import radians, sin, cos, sqrt, atan2

lat1, lon1 = radians(origin["communes"][0]["latitude"]), radians(origin["communes"][0]["longitude"])
lat2, lon2 = radians(dest["communes"][0]["latitude"]), radians(dest["communes"][0]["longitude"])

dlat, dlon = lat2 - lat1, lon2 - lon1
a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
distance_km = 6371 * 2 * atan2(sqrt(a), sqrt(1-a))
print(f"Paris → Marseille: {distance_km:.0f} km")

Market analysis

Aggregate business data by postal code. Combine with the SIRENE API to count businesses by sector in a given area.

Store locator

Find the nearest store by comparing GPS coordinates. The postal code API gives you the coordinates, and a simple distance formula does the rest.

Data coverage

The API covers all 39,000+ communes in metropolitan France and overseas territories:

• All 101 départements
• All 18 régions (13 metropolitan + 5 overseas)
• Paris arrondissements (75001-75020)
• Lyon arrondissements (69001-69009)
• Marseille arrondissements (13001-13016)
• Communes with multiple postal codes

Data is refreshed monthly from the official La Poste dataset.

Next steps

• Get your free API key, 100 requests/day
• API documentation
• Related: French company lookup, Business days, VAT validation