Another reminder - After GB and France declared war on Germany, France immediately invaded Germany, in the west, where mostly older German, reserve and even parade troops were stationed. France literally stayed within reach of the Maginot Line, as a sort-of backup force. So after Germany finished mopping up in Poland, it immediately turned on France and within a couple of weeks, via the lowlands, the war was effectively over, France capitulated, Vichy France was formed, etc. Hitler immediately sued for peace, but GB refused to back down and a period of a cold war with GB began.