That depends on which french. In WWII the french military command was the problem. Defense was planned around the Maginot line and I believe some of the leadership was quite willing to bargain with the Nazis. If your leaders surrender, what are the local troops to do. The Nazis also over ran Russian army groups. But Russia is a lot bigger and eventually orders against any surrendering were issued. Also Russian POWs were not treated very well. Stalin threw everything including the kitchen sink at the invaders.