Method
Start with the format, then test the edge cases
Read the definition and field structure first, review the limitations and official sources, then use the related tool with synthetic values.
Reference guides
Practical guides for formats, validation and test data
Clear definitions, field tables, edge cases, official sources and direct links to the OnSubmit tools that implement each workflow.
Published guides
Reference pages connected to working tools
Each guide explains a concrete format or validation boundary before linking to the relevant generator or checker.
Validation boundary
Correct format does not prove real-world existence
A checksum, postal-code pattern or locally coherent identifier can still be unassigned, inactive or unsuitable for a production transaction.
FAQ
Questions about French address test data
Does a correctly formatted French address prove deliverability?
No. A form can validate field structure and a city/postal-code pair without proving that the complete street address exists or can receive mail.
Why should French postal codes be stored as text?
They contain five characters and may start with zero. Numeric storage can remove that leading character.
What should a French address fixture contain?
Keep recipient, street, optional address line 2, postal code, locality, department, region and country in explicit fields.
Can test addresses be reproduced?
Yes. A stable seed, filter set, row count and dataset version can produce deterministic fixtures.
Which source defines French postal presentation rules?
La Poste publishes guidance on line order, maximum lines, postal-code placement and address presentation.