How To Correctly Format A French Phone Number Starting With 0 And Country Code 33

French phone numbers follow a structured national and international format that ensures clarity across borders. Whether you're placing an international call, adding contacts to your CRM, or filling out official forms, knowing how to properly format a French number—especially one beginning with 0 and including the +33 country code—is essential. Misformatting can lead to failed calls, undelivered SMS messages, or data inconsistencies in business systems.

This guide breaks down the correct formatting rules, explains when and why to use each variation, and provides practical examples for real-world applications.

Understanding the Structure of French Phone Numbers

French phone numbers are standardized by ARCEP (Autorité de Régulation de la Communication Électronique, des Postes et de la Distribution de la Presse), the national telecommunications regulator. All personal and business landline and mobile numbers in France consist of ten digits, typically written in groups of two digits: 0X XX XX XX XX.

The first digit after the initial zero indicates the type of line:

• 01: Île-de-France (Paris region)
• 02: Northwest France
• 03: Northeast France
• 04: Southeast France
• 05: Southwest France
• 06: Mobile phones
• 07: Mobile phones (newer range)

For example, a typical Paris landline might be 01 40 00 00 00, while a mobile number could be 06 12 34 56 78.

Tip: Always include spaces between pairs of digits when writing French numbers domestically—it improves readability and aligns with local conventions.

Converting from Domestic to International Format (+33)

When dialing a French number from abroad—or storing it in an internationally accessible system—the leading 0 must be replaced with the country code +33. This is not optional; omitting this step will result in connection failure.

The conversion follows a simple rule:

1. Remove the leading 0.
2. Prefix the remaining nine digits with +33.
3. Maintain spacing for readability: +33 X XX XX XX XX.

For instance:

• Domestic: 06 78 90 12 34 → International: [phone]
• Domestic: 01 23 45 67 89 → International: [phone]

Note that the space after +33 is usually placed after the area/mobile indicator (a single digit), followed by two-digit groupings.

Why Replace the Leading Zero?

The leading zero in France is known as the indicatif national—a trunk prefix used only within the country to route domestic calls. When calling internationally, the country code (+33) already signals that the number belongs to France, making the internal routing prefix redundant and incorrect.

“Using both the leading zero and +33 together is one of the most common telephony errors in global contact management.” — Laurent Moreau, Senior Telecom Consultant at Eurocom Solutions

Common Formatting Mistakes to Avoid

Even experienced professionals often make small but impactful errors when handling French numbers. Below is a comparison of correct versus incorrect formats.

Purpose	Correct Format	Incorrect Format	Reason
International Calling	[phone]	[phone]	Do not keep the leading 0 when using +33
SMS/Messaging Apps	[phone]	06 12 34 56 78	Apps like WhatsApp require full international format without spaces or zeros
Database Entry (Global CRM)	[phone]	01 23 45 67 89	Lacks country context; may cause confusion outside France
Local Use in France	01 23 45 67 89	[phone]	Overly formal for domestic use; unnecessary for local dialing

Tip: In digital systems, store numbers in E.164 format (e.g., [phone]) for compatibility with APIs, SMS gateways, and VoIP platforms.

Step-by-Step Guide: Converting Any French Number to International Format

Follow these steps whenever you need to convert a French domestic number for international use:

1. Start with the full domestic number: e.g., 07 45 67 89 01
2. Remove all spaces and punctuation: 0745678901
3. Delete the leading zero: 745678901
4. Add the French country code: [phone]
5. Reintroduce spaces (optional for readability): [phone]

This process works consistently whether the number starts with 01 through 07. The key principle remains: drop the 0, add +33, and ensure no extra characters interfere with automated systems.

Real-World Example: Business Contact Import

A marketing manager in Berlin imports customer data from a French partner. The spreadsheet includes mobile numbers listed as “06 88 77 66 55”. She plans to use these for a WhatsApp campaign via a cloud-based platform.

If she uploads the numbers as-is, the service rejects them because they lack country codes. After applying the conversion rule—replacing “06” with “+33 6” and removing spaces—the numbers become valid: [phone]. The campaign launches successfully, achieving a 92% delivery rate.

This case illustrates how proper formatting prevents technical failures and maintains professional reliability in cross-border operations.

Best Practices for Storing and Using French Phone Numbers

To maintain consistency across teams and tools, adopt the following checklist:

✅ Number Formatting Checklist

• Use +33 X XX XX XX XX for readable international display
• Store raw values in E.164 format ([phone]) in databases
• Never include parentheses, hyphens, or dots in backend storage
• Automate zero-stripping and +33 prefixing in form inputs where possible
• Train staff on format differences between local and international contexts

Additionally, consider implementing input validation in web forms. For example, if a user enters 06 12 34 56 78, the system can automatically detect the French pattern and offer to convert it to [phone] for global use—while preserving the original for local records.

Frequently Asked Questions

Can I dial a French number with +33 from within France?

Yes, technically you can, but it's unnecessary and may incur higher charges depending on your carrier. Within France, always use the domestic format (0X XX XX XX XX). The +33 format is intended for international callers or digital services requiring standardized input.

Why do some French mobile numbers start with 06 and others with 07?

Both 06 and 07 are designated for mobile services. Historically, 06 was the sole mobile prefix. As demand grew, 07 was introduced to expand capacity. There’s no functional difference—both work identically for calls and texts.

Is +33 0 considered a valid format?

No. The combination of +33 followed by a zero is invalid. Once you use the country code +33, the domestic trunk prefix (0) must be omitted. Correct format: [phone]—not [phone].

Final Thoughts: Accuracy Matters in Global Communication

Properly formatting a French phone number isn’t just about etiquette—it’s a technical necessity in our interconnected world. Whether you’re calling a client in Lyon, sending appointment reminders via SMS, or integrating data into a multinational CRM, precision ensures reliability and professionalism.

By understanding the role of the leading zero and the correct application of +33, you eliminate avoidable errors and streamline communication. Apply these standards consistently, educate your team, and verify entries systematically. Small attention to detail today can prevent costly miscommunications tomorrow.

💬 Have a formatting challenge with international numbers? Share your experience or ask questions in the comments—we’ll help you get it right.