I did a quick search but could not find any entry though, which is quite surprising because you can find people selling back their tickets, so there's gotta be a direct line somehow...
I think it takes 4 hours and 40 minutes to get there in a direct shot (according to people selling back their tickets)
Another way to do this would be to board onto a RER trainall the way to the Paris Gare-du-Nord terminus, then go all the way down across Paris to the Gare-Montparnasse station, and finally board a TGV to Lorient. That ain't the simplest solution, especially if your're travelling with children and luggage, the crossing of Paris may prove to be a nightmare.
But at least you will be assured that there will be trains to Lorient. You can book your RER ticket (also comes as a booklet, just in case) on the spot at the CDG station, and get to Montparnasse with the subway, taxis or underground RER lines. (this website may be useful www.transilien.com for finding possible itineraries) But if you go for that option, do make a reservation on your TGV seats online from Montparnasse to Lorient!
Otherwise, a plane airfare to Lorient from the airport would be around 94 Euros, which is quite expensive as compared to railways...
there is no train to the Eiffel tower.
To travel from Charles de Gaulle Airport to Paris by train, you can take the RER B train line. The train station is located within the airport, and you can purchase a ticket at the station or online. The journey takes about 30-40 minutes to reach central Paris.
To travel from Charles de Gaulle Airport to Montparnasse Train Station, you can take the RER B train from the airport to Denfert-Rochereau station, and then transfer to the metro line 6 to Montparnasse-Bienvenue station. The journey takes about 45-60 minutes.
The airport of Roissy - Charles de Gaulle is a few kilometers North of Paris. There are a suburban train link to Paris, taxi ranks, and bus lines.
From the Gare de l'Est Roissypole there is a bus, Line: 350 to Paris Charles de Gaulle Airport Train Station. The Paris Charles de Gaulle Airport Train Station is trafficed by the TGV. There is no direct train line from Paris Est to GDC airport. The best is to go to the Gare du Nord and get the RER B.
Right outside of Montparnasse train station there is a shuttle bus that goes to Charles De Gaulle Airport- it's about a 55 minute ride- give yourself a lot of time because of the inevitable traffic.
To reach Charles de Gaulle Airport using the metro system, you can take the RER B train line from central Paris. The RER B line has a direct connection to the airport terminals.
The main airport in Paris is Charles de Gaulle Airport. You can get there from the city center by taking the RER B train, which connects directly to the airport terminals.
The transfer time between terminals at Charles de Gaulle Airport (CDG) can vary, but typically takes around 30-45 minutes by shuttle bus or train.
To easily travel from Paris Metro to the airport, you can take the RER B train line, which connects directly to both Charles de Gaulle Airport and Orly Airport. Simply follow the signs in the Metro station to the RER B line and board the train heading towards the airport you need to reach.
To travel from Charles de Gaulle Airport (CDG) to Montparnasse train station in Paris, you can take the RER B train from the airport to Denfert-Rochereau station, and then transfer to the RER line C to reach Montparnasse station. The journey takes approximately 1 to 1.5 hours.
about 25 minutes from the moment you get on the train '"RER B". There are two stations in Charles de Gaulle Airport, CDG 1 and 2. Check what it yours. Hours of service and details on link.