Theres no way of logging in through the app by using the same identifier and password which is used to access ones account on the website, so theres no way of associating the session established through the appli with ones fidelity card numbers, ones saved frequent itineraries, ones ticket delivery preferences and so on. One can set certain parameters in this app to check on schedules, and to come to an approximation of the price one might get from the website, but ultimately one is forced to return to the website, and log in there to actually make the booking. In addition, as another reviewer has noted, unless one has a French 10-digit cell phone number, one cant use this app at all. In my case, I stay in France for 3 or 4 months per visit, the visits occuring every year or 18 months, and buy a cheap portable phone with a Mobicarte pre-installed in it each time I arrive. Therefore, my cell phone number is only valid for the present trip, and then only after Ive arrived, and have visited the Orange boutique to purchase this trips cheap phone. (My French homes fixed phone is always the same, but thats not a 06 number.) To use this app, I must lie, and provide the phone number from the last trips phone, which is really no longer valid. This unfortunate design choice is disappointing, because the user interface is fairly intuitive and straightforward. However, theres no good reason why this app shouldnt make use of the same login credentials which I present (and which I have presented for 10 years) when I make a booking on the website. Without that ability, its hardly worth using the appli at all.