[Al Schlageter]

Originally Posted by Old-Banger

What if France had walked into the Ruhr while Hitler was pre-occupied with Poland?

France did occupy part of the Saar.

Wiki
The French assault was to be carried out by roughly 40 divisions, including one armoured division, three mechanized divisions, 78 artillery regiments and 40 tank battalions. All the necessary forces were mobilised in the first week of September. On September 12, the Anglo French Supreme War Council gathered for the first time at Abbeville in France. It was decided that all offensive actions were to be halted immediately. By then, the French divisions have advanced approximately eight kilometres into Germany on a 24 kilometres long strip of the frontier in the Saarland area. Maurice Gamelin ordered his troops to stop not closer than 1 kilometre from the German positions along the Siegfried Line. Poland was not notified of this decision. Instead, Gamelin informed marshal Edward Rydz-Śmigły that half of his divisions are in contact with the enemy, and that French advances have forced the Wehrmacht to withdraw at least six divisions from Poland. The following day, the commander of the French Military Mission to Poland, General Louis Faury, informed the Polish Chief of Staff, General Wacław Stachiewicz, that the planned major offensive on the western front had to be postponed from September 17 to September 20. At the same time, French divisions were ordered to retreat to their barracks along the Maginot Line.