(disclaimer: I'm not a lawyer, I just have too much time on my hands). It seems that the EU regulations distinguish between additives, enzymes, and flavourings, and that sweeteners fall under additives.

Regulation on additives includes sweeteners alongside colours, emulsifiers, etc: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32...

Regulation on flavourings excludes sweeteners: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:32... (2. This Regulation shall not apply to: (a) substances which have exclusively a sweet, sour or salty taste;)