If you are arriving into Paris CdG on a SUNDAY, there are only 2 direct day trains from Paris Montparnasse to Bayonne, the 14.29 arriving Bayonne 19.44, and the 17.29 arriving 22.43. There is not a 10.10 train, it runs at 10.29 Mon-Fri only. If that may seem like bad news, the good news is there...