Thanks bwebel I hope this is still the case, though checking on ticket prices to go see a grandchild to be born this year I wonder if they allow this.
But even if we get the tandem to France we also understand there's a problem with fitting the tandem on the train we would take to where our daughter and son-in-law live in that they don't have bike spaces for tandem bikes and they have to be shipped on a freight train, a total non-starter after such a long flight.
We may investigate some of the take apart, Bike Friday, options, but I think we'll go to our daughters local bike shop when there this fall and talk with them about ideas, solutions. We have time before wife retires and touring begins.