Children must have proof of their right to free travel.
Children can access the closed networks (metro, train-rer, express tram) by travelling in the arms of an adult, or, for children in strollers, by asking the ticket office to open the side doors at the validation gates.
In case of crowds, children under 4 years old are invited to travel on the lap of the adult accompanying them. Priority seats are reserved for parents of young children in the trains.