You are following the footsteps of history.
The Germans lost at least two Somua tanks in that battle. (Finnish claim 5 tanks destroyed) Attached is a photo of the knocked out German Somuas on the road.
As a game play tip advance slowly and carefully, with 35 turns there is no need to rush. A good tactic would be to concentrate your forces in the North or South of the Finnish defense line and once in the line advance along it destroying the defenders one by one. Advancing on the road can be very deadly. Use your artillery to pin down the defenders or destroy fleeing enemy infantry, or maybe lay a smoke screen when crossing open fields.
Tank battalion 211 (Panzer Abteilung 211) was an interesting unit in the German army. It was entirely composed of French tanks captured in 1940. The Somua S-35 and Hotchkiss H-39 tanks. Also it operated in the front line. Elsewhere these obsolite French tanks were used mainly behind the front line in anti partisan duties or for crew training.
Tank battalion 211 arrived in Finland in June 23-26, 1941 and stayed there until the end of October 1944. Although the French tanks were useless against Soviet tanks like T-34 they were still quite useful for infantry support. Also early on in 1941 the Soviets mainly had light tanks like T-26 and BT-7 in the Lapland area which the French tanks were able to cope with.