Caesar did not engage the Tigurini in person, but Labienus, under his directions, routed them near the river ARAR.
"Plutarch-Lives-of-the-noble-Grecians-and-Romans"
Clough, Arthur Hugh
He having disposed his army in several bodies, and set officers over them, drew over to him all the country round about as far as those that lie upon the ARAR, and having intelligence of the opposition which Caesar now experienced at Rome, thought to engage all Gaul in the war.
"Plutarch-Lives-of-the-noble-Grecians-and-Romans"
Clough, Arthur Hugh
The ARAR is the Saone, which joins the Rhone at Lyons.
"Plutarch's Lives Volume III."
Plutarch