South end:Paris (Porte de Bagnolet) North end:A1 near Le Bourget Airport
The A3 Autoroute is a French autoroute located entirely within the départment of Seine-Saint-Denis, serving Montreuil-sous-Bois, Rosny-sous-Bois, and Bondy. Its southern terminus is an interchange with the Boulevard Périphérique at the Porte de Bagnolet, and its northern terminus is an interchange with the A1 near Le Bourget Airport. The A3 is 15 km long, and forms a part of European Route E15. A brief segment of its length is a concurrency with the A86. Two spur routes branch off from the A3: the A103 Autoroute and the A186 Autoroute. The first section of the roadway opened in 1969 between the Porte de Bagnolet and Bondy.