Solution : https://service.sap.com/sap/support/notes/574989 (SAP Service marketplace login required)
Key words : 
condition-based tax calculation, tax-free region, nota fiscal document, condition records created, condition type covers, icms tax base, total tax base, excluded base explicitly, zona franca processes, tax calculation
Related Notes : 
       
| 572141 | CRM Brazil: Tax base condition for Zona Franca not 0 |