Official rule text
[BR-DEX-12] The element "Third party payment description" BT-DEX-003 must be transmitted if the group "THIRD PARTY PAYMENT" (BG-DEX-09) is transmitted.
Official text (German): Das Element "Third party payment description" BT-DEX-003 muss übermittelt werden, wenn die Gruppe "THIRD PARTY PAYMENT" (BG-DEX-09) übermittelt wird.
Why this error occurs
This rule only applies when another field has a certain value (for example a payment means code or an invoice type). Your file triggers the condition but does not provide the data that then becomes mandatory, or provides data that is then forbidden.
How to fix it
Either change the triggering value so the condition no longer applies, or add/remove the dependent elements as the rule text describes. Check the condition in the XPath test above to see exactly which value triggers it.
What the validator checks
Checked element (context):
UBL
/ubl:Invoice/cac:PrepaidPayment[$isExtension]Test (XPath):
cbc:InstructionID[boolean(normalize-space(xs:string(.)))]Check your invoice
Drop your XML or PDF on the validator and every failed rule is linked to its page here. Free, no account, the file is not stored.
Same check via API:
curl -F file=@invoice.xml https://einvoicechecker.com/v1/validateRelated rules
BR-DEX-01The element … "Attached Document" uses a MIME code that is not permittedBR-DEX-02The value of "Invoice line net amount" of an "INVOICE LINE" or a "SUB INVOICE LINE"…BR-DEX-03A Sub Invoice Line must contain exactly one "SUB INVOICE LINE VAT INFORMATION"BR-DEX-04Any scheme identifier in … MUST be coded using one of the ISO 6523 ICD listBR-DEX-05Any scheme identifier in … MUST be coded using one of the ISO 6523 ICD listBR-DEX-06Any scheme identifier in … MUST be coded using one of the ISO 6523 ICD listBR-DEX-07Any scheme identifier for an Endpoint Identifier in … MUST belong to the CEF EAS code…BR-DEX-08Any scheme identifier for a Delivery location identifier in … MUST be coded using one…
Frequently asked questions
What does BR-DEX-12 mean?
BR-DEX-12 is a xrechnung rule: The element "Third party payment description" BT-DEX-003 must be transmitted if the group "THIRD PARTY PAYMENT" (BG-DEX-09) is transmitted.
Will my invoice be rejected because of BR-DEX-12?
Yes. BR-DEX-12 is flagged "fatal"; validators (KoSIT, Peppol access points, the German ZRE/OZG-RE portals) reject the invoice until it is fixed.
Which formats does BR-DEX-12 apply to?
XRechnung in UBL or CII syntax, including ZUGFeRD / Factur-X PDFs with the XRECHNUNG profile. Invoices to German public authorities (federal, state and municipal) must pass it. Syntax: UBL.
Source: XRechnung 3.0.2, schematron 2.6.0 (KoSIT, September 2026). Catalogue generated from the official schematron on 2026-10-14.