2555 20160701171707.0 ASTROimport-712 Martayan, C. 2008 The Gaia satellite: a tool for Emission Line Stars and Hot Stars The Gaia satellite will be launched at the end of 2011. It will observe at least 1 billion stars, and among them several million emission line stars and hot stars. Gaia will provide parallaxes for each star and spectra for stars till V magnitude equal to 17. After a general description of Gaia, we present the codes and methods, which are currently developed by our team. They will provide automatically the astrophysical parameters and spectral classification for the hot and emission line stars in the Milky Way and other close local group galaxies such as the Magellanic Clouds. Frémat, Y. Blomme, R. Jonckheere, A. Borges, M. de Batz, B. Leroy, B. Sordo, R. Bouret, J.-C. Martins, F. Zorec, J. Neiner, C. Nazé, Y. Alecian, E. Floquet, M. Hubert, A.-M. Briot, D. Miroshnichenko, A. Kolka, I. Stee, P. Lanz, T. Meynet, G. SF2A-2008 2008 499 http://esoads.eso.org/abs/2008sf2a.conf..499M published in NONREF