There currently is one option to travel by night train from Latour-de-Carol (France) to Paris (France), taking approximately 12 hours: Namely the INTERCITES DE NUIT n° 3970 operated by SNCF.
The French national railway SNCF serves several night train routes within France.
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, they are available. You can book an entire couchette compartment for private use. This can also be done for a group.
The main difference is in occupancy: four people per compartment in first class versus six in second class. Additionally, first class berths are slightly wider. First class passengers have access to showers at stations in Paris and Toulouse. Second class offers bicycle transport for 10 euros, which may interest cycling tourists.
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.