What is an accounting journal in France?

In practice, in France

The day book (livre-journal) is one of the mandatory accounting books, alongside the general ledger and the inventory book. In practice, it is broken down into auxiliary journals — one per type of operation — which together reconstitute the day book.

The rule that matters is not the breakdown but the irreversible chronology: once validated, an entry cannot be changed or deleted. A correction is made through a new, reversing entry. That property is what gives accounting its evidential value, and it is exactly what the tax authorities check in the accounting entries file.

In other words, the continuous, non-reversible numbering of documents is not an internal convention — it is what separates accounting that can be relied upon from a spreadsheet.

In Odoo

Each journal carries its own numbering sequence, and a validated entry becomes unchangeable.

The trap sits upstream of validation: as long as a document stays in draft, it remains editable, and nothing stops it being validated long after its date. Locking periods as you go is what guarantees that the recorded chronology matches the real one.

Common mistakes

• Changing or deleting a validated entry by working around the tool — the sequence becomes reversible, and the accounting entries file loses its value.
• Letting drafts pile up in periods already declared.
• Multiplying journals to the point that no one knows which one to use.