The MI 2N "Altéo" (French: Matériel d'Interconnexion à 2 Niveaux, English: two-level interconnection rolling stock), also known as the Class Z 1500 is a double-deck, dual-voltage electric multiple unit trainset that is operated on line A of the Réseau Express Régional (RER), a hybrid suburban commuter and rapid transit system serving Paris and its Île-de-France suburbs.

The 43 five-car trains were built by a consortium of French manufacturer Alstom (then known as GEC Alsthom) and Canadian conglomerate Bombardier.

The double-decker trains grew out of an effort to increase capacity on the RER A line, one of the world's busiest routes.

The Réseau Express Régional (RER) is a hybrid suburban commuter and rapid transit system serving Paris and its suburbs.

[2][3] The line started experiencing rapid growth in the 1980s, with traffic increasing by 9% per year on average.

That left the RATP and the SNCF looking for new equipment for the RER A and E lines, so in 1989 they decided to team up and issue a call for tenders.

As of 1 March 2022, 43 MI 2N Altéo trainsets were based at the Achères, Rueil-Malmaison, Sucy-en-Brie and Torcy RATP depots.