In 1936, Hitler recognized that his military was not strong enough to oppose the British ro the French at that moment in time, so when he ordered the German Army to march into the Rhineland, he gave the troops a secondary order: If the French offered any resistance, the troops were to retreat back to Germany.
Of course, France never offered any resistance and Hitler marched into the Rhineland unopposed.
But what if the French did offer resistance and the troops retreated back to Germany?