Travel to and from Versailles for Fireworks display

I am confused. I had received a reply yesterday stating that the rerc tickets and monteparnesee scnf train were interchangeable. However that post has been deleted. Since it is much closer from my hotel to Versailles using the rerc from st michael, I would like to leave from there. However the fireworks do not end until too late to take the rerc train back to the hotel. I am not going to have the time to waste purchasing an scnf ticket which is why I am concerned that an rerc ticket would not be accepted on a scnf train from Versailles to Montparnesee. Any help on this would be greatly appreciated.

Nancy, I am far from an expert but I do know that there is a SCNF ticket machine in the station where the RER C train pulls in. Maybe you can get your return ticket there right when you arrive in town?

The RER and SNCF are two different entities (think Metra vs Amtrak) and therefore I doubt they are interchangeable.

Hi Nancy, RER (Réseau Express Régional) is a type of train line, not a company. SNCF is the french national railway. RER C, as well as RER D and the northern part of RER B is operated by SNCF. Where do you want to start your return trip from? If you want to go to the Château de Versailles, it really makes more sense to travel to and from Versailles Rive Gauche, which is quite close from the Château, and where you can only take RER C.
Make sure you go to Versailles Rive Gauche and not Versailles Chantiers, or you will end up pretty far from the Château and end up losing a lot of time on the train. Let us know what other station you had in mind for the return trip, so I can check what is doable.

Thanks to everyone who have responded to my post. The station I would like to depart from Versailles is the Chantier station which is further from Versailles but has a later hour of departure if I am reading the train schedules correctly. Since the firework display does not end until close to midnight we would be able to see more of them while heading to the train station. That is what prompted my initial question if the Rer-c train tickets could be used on a scnf train because the departure time from the Chantier station is later than the Rive Gauche station.

Hi Nancy,
in this case no problem. Just keep in mind that RER C IS an SNCF train, so any A to B ticket you buy can get you from A to B on either the RER or the "trains de banlieue" which are also named Transilien (lines with letters like L, N, U...) Versailles-Chantiers is a station for RER C and Transiliens N and U, you can chose any train you like from there to any station in Paris. Just there is no need to buy a round trip ticket, it won't be any cheaper. By the way, I'm not sure they even exist for these lines. Buy a Paris-Versailles Rive Gauche ticket for the first part of your trip, and a Versailles Chantiers - Paris ticket for the return. Buy it in Paris before you go, at any RER or Transilien machine or at a ticket counter. If you buy it at the machine, it may not be able to sell you a Versailles-Paris ticket, but likely only a Paris-Versailles ticket. It doesn't matter, they are valid either way.

I just checked the Journey Planner on the RATP (Transports de Paris) site. For Sundays in August it did not list taking the RER C from Saint-Michel Notre-Dame to Versailles-Rive Gauche as being possible, It suggested other routes. I checked for Saint-Michel Notre-Dame to Invalides and was also given other routes. Perhaps that section will be closed for repairs.

RER C trains going to Versailles Rive Gauche usually start from Javel or Invalides, not from Saint-Michel. Both these stations can be easily reached from Saint-Michel with the Metro. You can use the same ticket for the metro and the RER part of your trip.

According to the RATP site, there is no RER C service between Saint-Michel Notre-Dame and Invalides until 18 August. Starting on that date there is REC C service from Saint-Michel Notre-Dame to Versailles-Rive Gauche every 15 minutes.