by the following day – 11 May – Gamelin began to realize that here, in the region of the Ardennes, was the Schwerpunkt of the German assault. Even so, the French command did not panic. They calculated the German advance in terms of French logistic achievement. The Germans would have to halt at the river Meuse. There they would regroup, bring up the artillery, and prepare for the river crossing. Gamelin ordered eleven French divisions to move to aid the threatened sector. He gave them top railway priority. It meant that the first elements of French support would arrive at the Meuse on 14 May, the last of them by 21 May. But by 13 May, the invaders, using road transport, were already at the Meuse and preparing to cross.

— Blitzkrieg by Len Deighton