The road runs south-west on the line of the D933 to La Plate Bourse where it diverges as a field track marked by communal boundaries as far as Ebblinghem. Here it becomes the D255 until it reaches the Lys at Pont d'Asquin. On the opposite bank it is marked by the D190 and boundaries as far as Therouanne where it enters by the east gate.

The link to the south gate of Cassel is not clear but the road probably branched from the Cassel to Pont de Thiennes road at the foot of the hill as indicated by a communal boundary. Passing the cremation cemetery in the sand at Oxelaere on the left and crossing the railway Bavinchove (Ger. Baving with hoof , the farm of Bavo) is reached on the right.

The remains of a bronze equestrian statue were found in the village in the 18th century. Work on the TGV Nord line revealed vestiges of a middle La Tene occupation and Gallo-Roman site.

At La Plate Bourse the road leaves the D933 on the right and continues in a straight line with Ebblinghem ( Ger. Humbaldingahem , the farm of the Humbaldingas, the people of Humbald) on the left to the N42.

Soundings made in the 19th century just before the Pont d'Asquin in the commune of Renescure (Ger. Ragin-hari with skure = stable) showed the road to be 6 metres wide and built of rammed earth and gravel to a thickness of 22 cm.

Gallo-Roman potter's ovens were found in Racquinghem (Ger. Raking with heim Racco's place) on the road just north of the Belle Croix. Roman tiles were found scattered alongside the road at Quiestede.

At several sites near the road at Cauchie tiles and pottery shards were found in 1993. Dates for these range from late La Tène to the Roman period

The road would seem to have joined the Roman road from Arras on the left bank of the Lys. There is no evidence for an ancient city wall at Therouanne. The town kept its Gaulish name (Taroanna, Tarvanna, Tervanna from Gal. tarvos = a bull) without an addition indicating that it was founded during the reorganisation of Gaul by Augustus. As the capital of the Morini it was probably of some importance prior to the Roman conquest. The town seems to have been twice destroyed by fire, once at the end of the second century C.E. and once linked to the invasions of the fifth century.