Smartest course would be to focus on the destruction of the transportation structure. Every possible meter of railroad track, every bridge, every culvert, every railway maintenance facility, every bit of rolling stock not evacuated, every fuel storage site, the power generators, transmission stations, the telegraph and phone exchanges,...
The Allies had to rebuild the railways and bridges west of Paris, but the task was much easier from Paris eastwards. As the key transportation hub of northern France a through sabotage of at least the railways would further cripple Allied logistics for August thru January.
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In order to do this, the German command would need to be OK leaving all those forces in a pocket for the Americans to capture. ...
And praying the French don't capture them first.