# DE-R-022

> If both supplier and customer are located in Germany, attached documents provided with an invoice in "ADDITIONAL SUPPORTING DOCUMENTS" (BG-24) shall have a unique filename (non case-sensitive) within the element ″Attached document″ (BT-125).

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/de-r-022

## Official rule text

If both supplier and customer are located in Germany, attached documents provided with an invoice in "ADDITIONAL SUPPORTING DOCUMENTS" (BG-24) shall have a unique filename (non case-sensitive) within the element ″Attached document″ (BT-125).