It’s sadly both allowed and common in France [1][2], the term they use is either “olives noires” (black olives) or “olives noires confites”.
[1] https://www.carrefour.fr/p/olives-noires-entieres-3560070340...
[2] https://www.carrefour.fr/p/olives-noires-denoyautees-crespo-...