Montreuil, sometimes unofficially referred to as Montreuil-sous-Bois, is a commune in the eastern suburbs of Paris, France. It is located 6.6 km from the centre of Paris in Seine-Saint-Denis. With a population of 109,914 as of 2018, Montreuil is the fourth most populous suburb of Paris after Boulogne-Billancourt, Saint-Denis and Argenteuil. It is located north of Paris's Bois de Vincennes in the 12th arrondissement, on the border with Val-de-Marne.