Airmail balloons, the so-called "ballons montés", are the solution to overcome isolation. Urged by the administration, Mr Felix Tournachon, called "Nadar" - photographer and aviation enthusiast - suggests to use manned hot air balloons to force the blockade.
And this works because, starting from 23rd September 1870 and for the following four months, 66 hot air balloons together with a free balloon with no name or passenger, described as "Non Dénommé", leave Paris with their postal load.