@Silvercents: it is a coin, a 10 euro from France. It's just not a round coin.
The casing is presumably how it was issued from the French mint. Unlike
TPG slabs, mint packaging is usually designed to be opened. As it isn;t round, there won;t be any screw-lock mechanism. You should be able to prise open the seam with a knife, screwdriver, or even your fingernails.
The case appears to have been damaged, at the bottom. Don't try opening it there, unless you've already tried elsewhere, as the plastic is more likely to break there.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis