The La Loi road bridge and the Vions railway viaduct were mined on 17 June.
Since 20 June, 23rd company, Infantry Detachment 145, held the two banks of the La Loi bridge with two important strongpoints, one on the right bank facing Culoz, the other at the outlet of the bridge on the left bank, reinforced by a 47mm gun.
12th company, DI 145 provided cover for the bridges on the Ruffieux-Chindrieux axis at the foot of Mount Clergeon.
During the night of 21 to 22 June, the German reconnaissance party of 66 Infantry Regiment (IR/66) coming from Virieu, came to contact with the right bank strongpoint, supported by the 47mm gun of the left bank.
Under enemy pressure, the defenders disengaged and withdrew to left bank.
Decision was then taken to blow up the road bridge, but the blast did not occur.
La Loi Bridge remained intact.
On the morning of 22 June, Germans triggered heavy artillery fire on the bridge defenders with their 8 x77mm guns positioned on the edge of Culoz. Fire was then shifted on Vions, Ruffieux and Chindrieux.
Firing ceased at the end of the morning and Germans began to drive on the bridge with tracked vehicles, but were repulsed, suffering heavy losses.
In the morning, German infantrymen discreetly crossed the Rhône in small boats, passing by the Brotalet islet upstream from the bridge, then, gaining a foothold on the left bank, fell back on the rear of the bridge, dispersing and capturing some of the defenders.
On 22 June at 1pm, 2 battalion, 93 IR crossed the bridge and entered Savoy.
The enemy's objective was to take Annecy and Aix les Bains through the line of passes and the Val de Fier.
12th company, ID145, set up in defense with several important strongpoints on axis Ruffieux -Chindrieux, at the crossroads leading to the bridges.
Its mission was to slow down the enemy as long as possible to allow the defense of the passes to be reinforced.
The defenders clung to the ground, despite artillery support provided to German infantry.
But, faced with German pressure and to avoid being overrun, they gradually retreated to Ruffieux strongpoint, which was taken in the afternoon.