# NFE-529

Source: https://xmlvalid.com/rules/NFE-529

> Rejeição: CST incompatível na operação com Contribuinte Isento de Inscrição Estadual [nItem: …] (CST …).

- Level: error
- Rule sets: SEFAZ authorisation rules of NF-e 4.00 MOC 7.0 Anexo I, NTs up to 2026.010
- Context: `nfe:infNFe/nfe:det`
- Test: `not($indIEDest = '2' and $cst = ('50', '51')) or ($cst = '50' and $cfop = ('1915', '1916', '2915', '2916', '5915', '5916', '6915', '6916', '1912', '1913', '5912', '5913', '1901', '2901', '5901', '6901'))`

In English: A sale to a receiver exempt from state registration (indIEDest 2) has CST 50 or 51 (CST 50 is allowed with the repair, demonstration, exhibition and industrialisation CFOPs).

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