What does the French Phone Number regex match?

Matches a French metropolitan phone number in domestic or international format.

Is the French Phone Number regex ReDoS-safe?

Yes. Manually audited and tested against ReDoS attack strings. Anchors and possessive-style constraints prevent runaway backtracking paths.

How do I use this regex in python?

import re pattern = re.compile(r'^(?:\+33[\s.-]?|0)(1|[2-9])[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})$') is_valid = bool(pattern.match(input_str))

Localization/Phone Numbers

Verified Safe

French Phone Number Regex for Python

/^(?:\+33[\s.-]?|0)(1|[2-9])[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})$/

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching french phone number, 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

Python

# French Phone Number
# ReDoS-safe | RegexVault — Localization > Phone Numbers

import re

french_phone_number_pattern = re.compile(r'^(?:\+33[\s.-]?|0)(1|[2-9])[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})[\s.-]?([0-9]{2})$')

def validate_french_phone_number(value: str) -> bool:
    return bool(french_phone_number_pattern.fullmatch(value))

# Example
print(validate_french_phone_number("+33 1 42 34 56 78"))  # True

Test Cases

Matches (Valid)	Rejects (Invalid)
`+33 1 42 34 56 78`	`+33 0 42 34 56 78`
`01 42 34 56 78`	`42 34 56 78`
`+33612345678`	`+44 1 42 34 56 78`
`06 12 34 56 78`	`01 42 34 567`
`09 12 34 56 78`	—

When to use this pattern

This pattern is drawn from the Localization > Phone Numbers 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

French overseas territories (DOM-TOM) use different prefixes — Réunion is +262, Guadeloupe/Martinique/French Guiana are +596/+594, New Caledonia is +687. These are not matched by this pattern.

Technical Notes

French numbers are always 10 digits in domestic format (excluding leading 0). Zones: 01 (Paris), 02 (northwest), 03 (northeast), 04 (southeast), 05 (southwest), 06-07 (mobile), 08 (special), 09 (VoIP). +33 replaces the leading 0.

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