In the lounge you can have full meal + desert, wine, complimentary 30 min facial treatment, showers, relaxing area. If you fly in P for the first time then I recommend at least 4 hours (or in your case spend ~ 2 hrs on arrival, ~ 2 hrs before departure - I don't think you'll have issues reentering after you leave the airport, feel free to ask the staff on the topic / getting escort through security). Once you fly P again I'd say 2 hours is absolute minimum to get: (1) food + wine , (2) facial treatment and since you arrive after long haul then add time for shower so you're looking for 2h30 min - 3h. After all, it's still only a lounge, so no matter how nice it is, you'll be just passing time if you stay longer.

btw. When I flew 2 long-haul legs DXB-CDG-SFO in P (with 4 hr layover) I learned that you'll get a lot of food/wine on the trip, to a point when you'll need to plan ahead a bit to prevent from having too full stomach. I would then recommend not to each very much while you're out in Paris or assume you'll eat lightly while flying in J to JFK.