Pessac is a commune in the Gironde department in Nouvelle-Aquitaine in southwestern France. It is a member of the metropolis of Bordeaux, b…Pessac is a commune in the Gironde department in Nouvelle-Aquitaine in southwestern France. It is a member of the metropolis of Bordeaux, being the second-largest suburb of Bordeaux and located just southwest of it. Pessac is also home to Bordeaux Montaigne University and the Institut d'études politiques de Bordeaux.