The road begins in Paris at the Porte de Pantin becoming the Avenue Jean Lolive.
After 15 km the RN 3 enters Meaux after which it crosses the Marne and heads through the Forêt de Montceaux.
The road crosses the Marne again at Château-Thierry and heads east through the Bois de Condé.
At Etain, the road passes southeast and then through Jarny and then over a ridge of hills and the Bois de Vaux into Metz and the River Moselle.
The road continues over the hills now over 300 m high before a steep incline down into Saint-Avold now only 4 km south of the frontier with Germany.