There currently is one option to travel by night train from Aurillac (France) to Paris (France), taking between approximately 10 and 11 hours: Namely the INTERCITES DE NUIT n° 3790 operated by SNCF.
The French national railway SNCF serves several night train routes within France.
In their night trains, they typically offer two types of carriages: seats and couchettes, with the latter available in first and second class.
In the couchette carriages, you travel in 4-person compartments (first class) or 6-person compartments (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.
First class berths are slightly wider than in second class and there are only four berths per compartment. Advantage of first class: In Paris and Toulouse, there are showers at the stations for first class passengers. In second class, six travelers share each compartment. For cyclists, it's possible to bring a bicycle in second class for an additional fee of 10 euros.
There is no dining car on board the Intercités de Nuit. It's recommended to bring your own food or eat in Paris before departure. It's possible to pre-order food and drinks. In first class, a small breakfast is offered. Each passenger receives a 'night kit' with a refreshing towelette, dental cleaning tablet, sleep mask, earplugs, and a small bottle of water.