There currently is one option to travel by night train from Paris (France) to Albi (France), taking approximately 14 hours: Namely the INTERCITES DE NUIT n° 3755 operated by SNCF.
The National Company of the French Railways (SNCF) operates a handful of lines throughout continental France.
In their night trains, they typically offer two types of carriages: seats and couchettes, with the latter available in first and second class.
The couchette carriages offer space for up to four people per compartment in first class and six people in second class. The berths are simply designed in both classes and are about 1.9 meters long.
Yes, for more privacy, entire 4-person compartments can be booked exclusively. This can also be done for a group.
In first class, only four people share a compartment, the berths are wider, and travelers have access to station showers in Paris and Toulouse. Second class accommodates six people per compartment and allows bicycles to be brought for an additional fee of 10 euros – a plus for cyclists.
The night trains don't have a dining car, so it's advisable to bring your own food or eat before departure. You can also pre-order salads, sandwiches, and drinks. First class passengers receive a small breakfast. All travelers get a night kit with refreshing towelette, dental hygiene product, sleep mask, earplugs, and a bottle of mineral water.