 Certainly Gerstner's actions in support of the French resistance agenda became anything but covert in 1946, and some, at least, of the more pressing evidence supporting it appears to sourced, directly or indirectly, from his own writings.France was invaded in May/June 1940.The military phase of the operation was completed much more rapidly than French military planners had expected, and in July 1940 Karl-Heinz was sent back to Paris as an "Academic support assistant in the Economy Department" at the German embassy in Paris.