The novelty of taking the Paris Metro wears off rather quickly especially if you’ve ever had to navigate the subterranean Châtelet metro station. I quote the following information from a recent web query. “Châtelet is a station on lines 1, 4, 7, 11 and 14 of the Paris Métro in the centre of medieval Paris and the 1st arrondissement”. Traveler’s translation — there are 5 metro lines intersecting in one station; five levels of Metro lines, and I guarantee you that your corresponding line is absolutely the farthest away from where you first arrived.
You will travel up and down stairs and through many tunnels. If you had any sense of direction before you arrived at Châtelet, you will be throughly reoriented upon departing. And, by the way, you’re underground and can’t see anything of Paris, the world’s most beautiful city.
There are also many bus lines running above ground at Châtelet. I cross checked my bus map with Google Maps and happily noticed that **my** favorite bus Line 21 arrives at Place de Châtelet right after the Cité–Palais de Justice stop (direction Gare Saint Lazare). If you prefer to use the Metro and need to use the Châtelet station, I suggest you take a bus first to Sainte-Chapelle and then st/roll across the La Seine before being swallowed up by the Châtelet Metro station.
I wholeheartedly encourage you to hop or roll onto a Paris bus for an eye opening experience at the street level.