There currently are a variety of options to travel by night train from Aurillac (France) to Paris (France), taking between approximately 10 and 12 hours: Namely the INTERCITES DE NUIT n° 3790 and the INTERCITES DE NUIT n° 3792. These lines are operated by SNCF.
In France, a few night train lines are operated by the state-owned SNCF.
These night trains typically feature seating carriages and couchette carriages 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, it's possible to reserve an entire couchette compartment as a private compartment. 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.
You should bring your own food as there is no restaurant on board. Alternatively, you can pre-order meals and drinks or eat before departure. First class travelers receive a small breakfast. Each passenger receives a night kit with refreshing towelette, dental cleaning tablet, sleep mask, earplugs, and water.