I used the Air France arrivals lounge the other day, when arriving into Paris–CDG from Detroit in business-class on Delta.

Unlike London–Heathrow, Delta does not promote it. If you didn't know about it nobody would tell you. It took about 10 minutes to walk there from baggage claim. The lounge is basically hidden away behind check-in desks with almost no signage.

Inside, it's pitiful. The breakfast buffet was nearly empty and never restocked during the 40 minutes I was there. No alcohol or cooked-to-order breakfast. They do have unlimited coffee and unlimited Coke or Coke Zero, among other non-alcoholic beverages. I used the shower, which was great. I think having a shower is the only reason you would make the trek here from 2-E.