French Code Postal Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching french code postal, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# French Code Postal
# ReDoS-safe | RegexVault — Localization > Postal Codes

import re

french_code_postal_pattern = re.compile(r'^(0[1-9]|[1-8][0-9]|9[0-8])[0-9]{3}$')

def validate_french_code_postal(value: str) -> bool:
    return bool(french_code_postal_pattern.fullmatch(value))

# Example
print(validate_french_code_postal("75001"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Postal Codes category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

French department codes run 01-95 (metropolitan), 97 (overseas departments: 971=Guadeloupe, 972=Martinique, 973=French Guiana, 974=Réunion, 976=Mayotte). 99 is excluded (reserved). Paris arrondissements are 75001-75020.