I'm not sure what that table is showing, but it's not what you are implying. Niger is France's plurality supplier, so them showing 5% is clearly measuring something else.
Beyond that, France is not importing from Niger in the nominal sense. A French state owned company, in Niger, mines the uranium, and then gives Niger a token royalty on profits. So if they claimed e.g. $100, you'd expect about $5.50 of that (unless Niger was able to negotiate a better deal since 2015) to go to Niger. So their "real" cost would be the $5.50 plus labor/supplies.
Beyond that, France is not importing from Niger in the nominal sense. A French state owned company, in Niger, mines the uranium, and then gives Niger a token royalty on profits. So if they claimed e.g. $100, you'd expect about $5.50 of that (unless Niger was able to negotiate a better deal since 2015) to go to Niger. So their "real" cost would be the $5.50 plus labor/supplies.