Thanks both for your help!

Goldorak: I will definitely call the Première line beforehand. I was thinking they would be able to "link" my bookings as both are under the same FB Plat #, and will additionally check luggage all the way
rdnnr: I am actually French, born and raised in Paris - my goal there was more to go and have coffee with friends during the layover. Fully agreed that 6 hrs would not be enough for tourism...