It's the tow hook cover. I don't know what model Merc that is but Amazon has some.
https://www.amazon.com/s?k=mercedes+tow+hook+cover&i=automotive&ref=nb_sb_noss_2
EDIT: https://www.amazon.com/Front-Bumper-Mercedes-C63AMG-2058850724/dp/B07VHH89YN/ref=sr_1_3?dchild=1&keywords=mercedes+tow+hook+cover+w205&qid=1619213752&s=automotive&sr=1-3 For W205