Our advice:

• If you buy your tickets for a foreign railway, find out before departure about the conditions for using the tickets (check-in at a station counter, compulsory stamping, etc.) and the documents to be presented in the event of a check (discount card, proof of identity, payment card used for the booking, etc.). The documents required may differ from one railway undertaking to another. If you do not present the required documents, you may be fined and charged the appropriate fare if you do not have proof of discount for example.
• Check before departure whether all tickets you booked online are electronic tickets or whether you will need to collect paper versions at the station.
• If you are travelling across the borders, make sure you take your valid passport or identity card with you. If there are no systematic checks on departure, customs or the police may carry out unannounced checks during the journey.
• French minors travelling without (one of) their parents are also required to travel with a valid identity document and an authorisation to leave the country. If your children have another nationality, check the travel conditions as well.