SEPA Requirements for an Extended Character Set (UNICODE Subset) - Best Practices 21.12.09
Within the SEPA schemes, unless otherwise agreed, only a limited set of Latin characters may be exchanged. This restriction was agreed in order to overcome the complexity that would result if all European language based characters were to be exchanged between all adhering banks.
However by prior agreement banks may exchange additional characters, perhaps through bilateral/multilateral agreements or via an agreed AOS (Additional Optional Service).
Although restricting SEPA to a limited set of Latin characters has avoided complexity and minimised the impact on bank processing systems it has other less positive consequences. Therefore EPC have provided a common conversion tool (a SEPA conversion table) to optionally extend the Latin character set to cater for all European local languages. The tool may be used to protect legacy systems, and is accompanied by a set of best practices covering the intended usage of the conversion table within SEPA.