Paris-St Dizier-Nancy-Strasbourg-Germany The road begins in Central Paris at the Porte Doree and a junction with the RN 6 a separate branch starts in the Bois Vincennes with a junction with the RN 34 before heading south through the park and meeting the other branch the Avenue de Gravelle.
It then passes through Chennevières-sur-Marne and an industrial area before reaching open countryside and the northern edge of the Forêt de Notre-Dame.
The road has a junction with the RN 104 and becomes a dual-carriageway and now bypasses Ozoir-la-Ferrière and then Gretz Armainvilliers south of the Forêt d'Armainvilliers.
The road passes over open flat countryside increasingly sparsely populated reaching RN 77 and A 26.
The RN 4 heads east up out of the valley climbing to 350 m in much steeper countryside which is also more wooded.
The road then passes through the Forêt de Ligny before entering Ligny-en-Barrois itself in the Ornain valley crossing the Canal du Rhein.
The road passes into the town of Toul overlooked by wooded highlands including Bois de Grammont (424 m) and enters the valley of the river Moselle.