ESA has adopted Ariel (Atmospheric Remote-sensing Infrared Exoplanet Large-survey), the 4th medium-class space mission of its Cosmic Vision program. Ariel is expected to be launched in 2029 by Ariane 6 from the Guiana Space Centre in Kourou. The French team, composed of CNES, CEA and CNRS, has taken charge of the design, production and delivery of the AIRS spectrometer. Pierre Olivier Lagage, astrophysicist at Irfu, is one of the 2 co-PI for the ARIEL consortium; the other co-PI is Jean-Philippe Beaulieu from IAP.