On June 16 the 1st and 2nd Panzer Divisions were pushing southward toward the Saone River while the 20th Motorized Division screened their northern flank and fought its way eastward toward the Swiss border. The trapped French 8th Army was their obvious target, and it could do nothing but wait for the hammer blow to fall. Even worse, the French didn't know where to deploy their forces since the Germans could also strike at them from the east by crossing the Rhine or even by cutting through Switzerland (they did cross the Rhine on June 15). So the 8th Army opted to cover all its flanks and spread its forces thinly, ordering Groupement Duluc (named after its commander) to deploy on the French west flank on a front more than 70 kilometers long. Having lost many of the units under his command in a previous battle with 20th Motorized, Dulac deployed what troops he could muster around small cities that had been fortified in a last effort to stem the tide.

The motley force defending Luxeuil was poorly-balanced, with more artillery than infantry. In addition, their scattered troops were set up to defend a line of villages along a river instead of defending the roads the Germans would have to use in their attack. Some ancient FT17 tanks completed the picture of a lost cause, and the French positions were overwhelmed by the Germans who then advanced to the northeast to complete the encirclement of 8th Army.