I flew ATL-CDG-FCO and return in La Premiere. Since I hadn't read anything about ATL LP service, here's what happened.
Greeted by two AF agents and checked in by DL agent at ticket counter check in. One of the AF agents accompanied us through the crew/handicapped lane of TSA which saved some time. Precheck is closed at this time of day (after 5:30) so TSA line can be long. I was curious to see if there would be some special setup in the DL Skyclub for AF LP; to my delight, the offer was unlimited free food and drink at Ecco, which is my favorite restaurant in E and F. Had excellent mussels with crusty toasted bread. Greeted by more people at restaurant, such as Food and Beverage manager (HMS Host) and another AF agent. Offered early or late boarding. We selected late boarding onto the A380.
Besides my wife and I, there were two other passengers; one was a day of departure paid upgrade (we spoke to him at the lounge). The seats were not in as bad shape as I had feared. The IFE is ancient, but I was able to make it work by using the wired controller arrows and buttons. Service was excellent with one and a half flight attendants for the 4 passengers.
Lounge: had a long layover, so we could take advantage of massage and facial at the spa. My wife received some free samples with her facial. I had the veal special and baba au rhum (Diplomatico Reserva Exclusiva) which were both great. Unusually, I observed several people at the bar. It was a busy time with about 15 people in the lounge.
On the way back: We had only 30 minutes in the CDG lounge but this was enough time for me to get the fish and my wife to get the foie gras. Upon boarding, we found that we were the only passengers in LP!! Caviar served upon boarding with mother of pearl spoon, and Veuve Cliquot 2006. Had langoustine and then beef. For the second meal/snack, I asked for the custom salad from the lunch course.
In ATL, two airport agents greeted us at the plane and they walked us all the way to the Parking shuttle. I don't know if there was really any time savings by being accompanied. We used Mobile Passport since my wife doesn't have Global Entry; fortunately, there was no line whatsoever at immigration. The luggage for LP does not come out with the regular luggage but goes onto a small linear conveyor belt for crew. A slight problem was that the belt was quickly filled with crew baggage which then stopped the belt. The accompanying agents couldn't touch luggage so they had to find somebody who could move the crew bags off the belt. We lost a few minutes in this process. Between pulling up to the jetway and reaching the street curb took no more than 30 minutes.