Paris Charles de Gaulle airport has two oneworld lounges: an American Airlines Admirals Club and a Cathay Pacific lounge. Both are located between Terminals 2A and 2C.
The Admirals Club at CDG is the best and nicest Admirals Club I’ve been to. And that’s comparing to lounges like the one in Narita and the Flagship lounges. The club has a nice space that’s well decorated and designed. There’s plenty of seating, universal power outlets, and large windows where you can some natural light and nice views of airplanes.
The food selection is also great for an Admirals Club. This club is only open in the mornings (6am to 12pm), but they have a great breakfast spread. They have all of the typical American-ish hot items (e.g., omelets, frittatas, eggs, bacon, sausage, potatoes, tomatoes), as well as a good cold selection of breads, salads, meats, and cheeses. Food seemed to be replenished relatively frequently, so things seemed fresh.
I didn’t stick around too long in this club because I also wanted to check out the Cathay Pacific lounge next door, but the Admirals Club wasn’t too crowded just before 11am (which was right after a bank of flights had just departed). The two lounges are literally right next to each other, so you can take your pick, but I’d probably choose the Admirals Club for breakfast and the Cathay Pacific lounge for lunch. The Cathay Pacific lounge is also probably a tad less crowded in the mornings.