There currently is one option to travel by night train from Bretenoux (France) to Paris (France), taking between approximately 9 and 10 hours: Namely the INTERCITES DE NUIT n° 3790 operated by SNCF.
The National Company of the French Railways (SNCF) operates a handful of lines throughout continental France.
SNCF night trains are equipped with standard seating carriages and couchette carriages offered in two comfort classes.
Couchette carriages generally have 4-person compartments in first class and 6-person compartments in second class. The berths are simply designed in both classes and are about 1.9 meters long.
Yes, they are available. You can book an entire couchette compartment for private use. 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.