The Carte Améthyste is an annual season ticket for the elderly and disabled (aged over 20).
It allows free travel in second class on services provided by the RATP and the SNCF in the Île-de-France.
It can also be used on the night bus service Noctilien, but not to get to or from the airports, nor buses that have special fares.
[1] The card is valid for a year from the date of issue, and can be renewed annually.
It can be combined with the Carte Rubis, which is designed for use on the Optile bus network.