I bought tickets for my niece Paris-Venice on a night train; I had trouble with the tgv.com site and my french is not that great.
I could not figure out exactly what I wanted and wanted to make sure they get a room by themselves. I also did not want them to have to go to the window and pick up the tickets; I wanted them to have the tickets before they leave.
I ended up calling rail europe in the US and told them what I wanted. Their price was higher and they were able to cut it down so it came out to be about 5-7% higher than TGV website - shipping of tickets included. It was worth it.