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 (4.1 mi) from the centre of Paris, in the Seine-Saint-Denis department and in the Métropole du Grand Paris. With a population of 111,367 as of 2020, Montreuil is the third most populous suburb of Paris after Boulogne-Billancourt and Saint-Denis. It is located north of Paris's Bois de Vincennes, on the border with Val-de-Marne.

Seine-Saint-Denis is a department of France located in the Grand Paris metropolis in the Île-de-France region. In French, it is often referred to colloquially as quatre-vingt treize or neuf trois, after its official administrative number, 93. Its prefecture is Bobigny.