# BR-DE-16 Seller tax identifier must be provided for taxable VAT categories

Under § 14 Abs. 4 Nr. 2 of the German VAT Act (UStG) and XRechnung rule BR-DE-16, whenever an invoice contains taxable line items or tax breakdown categories (specifically categories S, Z, E, AE, K, G, L, or M), the seller must declare either a valid VAT identification number (USt-IdNr., BT-31), a local tax number (Steuernummer, BT-32), or the VAT identifier of their tax representative (BT-63). German tax law requires this identification to ensure tax enforceability and enable the recipient to claim input VAT deduction (Vorsteuerabzug).

## Problem Description

> **ERROR**: German XRechnung rule (KoSIT, BR-DE) · XRechnung 3.0

## Context and Significance

Under German tax compliance, an invoice without seller VAT ID or tax number is defective and invalidates input VAT deductions. Rule BR-DE-16 enforces this requirement across all taxable invoice profiles.

## Solution

In your ERP company settings, configure your VAT registration number (e.g. DE123456789) or local tax number (e.g. 27/123/45678). In UBL 2.1 syntax, for a VAT ID, populate <cac:PartyTaxScheme><cbc:CompanyID>DE123456789</cbc:CompanyID><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:PartyTaxScheme> under <cac:AccountingSupplierParty><cac:Party>. For a local tax number (Steuernummer), set <cac:TaxScheme><cbc:ID>FC</cbc:ID></cac:TaxScheme>. In UN/CEFACT CII syntax, populate <ram:SpecifiedTaxRegistration><ram:ID schemeID="VA">DE123456789</ram:ID></ram:SpecifiedTaxRegistration> (or schemeID="FC" for Steuernummer) under <ram:SellerTradeParty>.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-DE-16)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-DE-16)

## Valid Examples

- Seller declares VAT identifier BT-31 = "DE123456789" with TaxScheme "VAT"
- Seller declares local tax number BT-32 = "27/123/45678" with TaxScheme "FC"

## Invalid Examples

- Taxable invoice using category S where seller party contains no PartyTaxScheme or SpecifiedTaxRegistration element
- Seller party declares only company name and address without any VAT identifier or tax registration number

## Code Examples

### Valid XML
```
<cac:PartyTaxScheme>
  <cbc:CompanyID>DE123456789</cbc:CompanyID>
  <cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme>
</cac:PartyTaxScheme>
```

### Invalid XML
```
<cac:PartyLegalEntity>
  <cbc:RegistrationName>Musterfirma GmbH</cbc:RegistrationName>
</cac:PartyLegalEntity>
```

## Affected Fields

- [BT-31 Seller VAT identifier](/resources/xrechnung/bt-31-seller-vat-identifier)
- [BT-32 Seller tax registration identifier](/resources/xrechnung/bt-32-seller-tax-registration-identifier)
- [BT-63 Tax representative VAT identifier](/resources/xrechnung/bt-63-seller-tax-representative-vat-identifier)

## Related Rules

- [BR-CO-09](/resources/kosit-validator-errors/br-co-9-vat-identifier-must-have-iso-country-prefix)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.