The Hôtel des Invalides was (and a part still is) an hospital for soldiers. It's now a huge museum dedicated to the history of wars, from the Middle-Age to the Second World War, with impressive collections of armours and weapons of all sort, beautifully presented, as well as costumes and flags.
But the Dôme Church, with its golden Coupole, dedicated to Napoleon tomb, is also something to see! The inside of the church is light and beautiful, and the tombstone, made in red marble, is big enough to contain, I would say, ten bodies! It's surrounded by the tombs of four important marshals, Foch, Duroc, Lyautey, and Bertrand. On the walls, all around the Emperor monumental coffin, are graved pictures of him and texts about what he's done. Everything is nearly as fastuous as for a pharaon!!