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error Class A

BR-DE-02 Seller Contact Telephone

What this rule checks

BR-DE-02 verifies that the field BT-42 (Seller contact telephone number) is present in the invoice. Technically, it checks whether the cbc:Telephone element exists within cac:AccountingSupplierParty/cac:Party/cac:Contact and is not empty.

Why this rule exists

In German e-invoicing, providing seller contact details is a mandatory requirement that goes beyond the European base standard EN 16931. The rationale: when an invoice recipient has questions or objections about an invoice, they must be able to reach the invoicing party directly and without friction.

The telephone number is a particularly important channel because many clarification cases in the B2G (Business-to-Government) domain are time-sensitive and can be resolved more quickly by phone than by email. Together with BR-DE-03 (email) and BR-DE-06 (contact name), BR-DE-02 forms a trio of rules that ensure the seller contact block is complete.

What triggers a failure

The rule fails when:

  • The cbc:Telephone element in the cac:AccountingSupplierParty/cac:Party/cac:Contact block is missing
  • The cbc:Telephone element is present but empty (e.g., <cbc:Telephone></cbc:Telephone>)
  • The entire cac:Contact block is missing (this simultaneously triggers BR-DE-02, BR-DE-03, and BR-DE-06)

Failing XML example

The following example shows a seller contact block with a name and email but no telephone number:

<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyName>
      <cbc:Name>Musterfirma GmbH</cbc:Name>
    </cac:PartyName>
    <cac:PostalAddress>
      <cbc:StreetName>Hauptstraße 1</cbc:StreetName>
      <cbc:CityName>München</cbc:CityName>
      <cbc:PostalZone>80331</cbc:PostalZone>
      <cac:Country>
        <cbc:IdentificationCode>DE</cbc:IdentificationCode>
      </cac:Country>
    </cac:PostalAddress>
    <cac:PartyTaxScheme>
      <cbc:CompanyID>DE123456789</cbc:CompanyID>
      <cac:TaxScheme>
        <cbc:ID>VAT</cbc:ID>
      </cac:TaxScheme>
    </cac:PartyTaxScheme>
    <cac:PartyLegalEntity>
      <cbc:RegistrationName>Musterfirma GmbH</cbc:RegistrationName>
    </cac:PartyLegalEntity>
    <cac:Contact>
      <!-- ERROR: Telephone number is missing -->
      <cbc:Name>Max Mustermann</cbc:Name>
      <cbc:ElectronicMail>rechnung@musterfirma.de</cbc:ElectronicMail>
    </cac:Contact>
  </cac:Party>
</cac:AccountingSupplierParty>

The fix

Add the cbc:Telephone element to the seller’s Contact block:

<cac:AccountingSupplierParty>
  <cac:Party>
    <cac:PartyName>
      <cbc:Name>Musterfirma GmbH</cbc:Name>
    </cac:PartyName>
    <cac:PostalAddress>
      <cbc:StreetName>Hauptstraße 1</cbc:StreetName>
      <cbc:CityName>München</cbc:CityName>
      <cbc:PostalZone>80331</cbc:PostalZone>
      <cac:Country>
        <cbc:IdentificationCode>DE</cbc:IdentificationCode>
      </cac:Country>
    </cac:PostalAddress>
    <cac:PartyTaxScheme>
      <cbc:CompanyID>DE123456789</cbc:CompanyID>
      <cac:TaxScheme>
        <cbc:ID>VAT</cbc:ID>
      </cac:TaxScheme>
    </cac:PartyTaxScheme>
    <cac:PartyLegalEntity>
      <cbc:RegistrationName>Musterfirma GmbH</cbc:RegistrationName>
    </cac:PartyLegalEntity>
    <cac:Contact>
      <cbc:Name>Max Mustermann</cbc:Name>
      <!-- CORRECT: Telephone number added -->
      <cbc:Telephone>+49 89 1234567-0</cbc:Telephone>
      <cbc:ElectronicMail>rechnung@musterfirma.de</cbc:ElectronicMail>
    </cac:Contact>
  </cac:Party>
</cac:AccountingSupplierParty>

Edge cases and common mistakes

No prescribed format: The XRechnung specification does not require a specific telephone number format. All of the following variants are valid:

  • +49 89 1234567-0 (international with extension)
  • 089/1234567 (national)
  • +49891234567 (unformatted)

However, the international E.164 format (e.g., +4989123456700) is recommended as it is machine-readable and unambiguous.

Central switchboard number is acceptable: A personal direct dial number is not required. A main switchboard number or accounting department number is sufficient — as long as the invoice recipient can actually reach a contact person through it.

Interaction with BR-DE-03 and BR-DE-06: The three rules BR-DE-02 (telephone), BR-DE-03 (email), and BR-DE-06 (contact name) together form the requirement for a complete seller contact. If the entire cac:Contact block is missing, all three rules are violated simultaneously. It is recommended to always populate the Contact block completely with name, telephone, and email.

XPath: The exact path for validation is:

/ubl:Invoice/cac:AccountingSupplierParty/cac:Party/cac:Contact/cbc:Telephone

For CII (Cross Industry Invoice), the equivalent path is:

/rsm:CrossIndustryInvoice/rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:DefinedTradeContact/ram:TelephoneUniversalCommunication/ram:CompleteNumber

Empty elements: An empty <cbc:Telephone/> or <cbc:Telephone></cbc:Telephone> is not accepted as a valid value. The element must actually contain content.