Jena is everywhere. In this case the Iéna metro station underneath Place d’Iéna, which divides the Avenue d’Iéna, which leads down to Pont d’Iéna at the foot of the Eiffel tower. Paris, exactly.
Why did they name it that way? Napoleon, battle, 1806. Check your history book.

(but the real Jena metro is a restroom underneath the fountain on Jenas market place. 😉)