While the Vichy administration collaborated with the Germans, hoping for a swift end to the war, resistance fighters sprung everywhere and organised against the invaders. As a counter-measure, the Nazi regime deployed its intelligence service (the Gestapo) and its security police.
As the central icon of Paris, the Eiffel tower became somewhat of a symbolic battleground. Hitler ordered its demolition, but his orders were never carried out, and the Germans would later deck it with Nazi banners.
In 1944, the year of the liberation of Paris, the tower became a different battle arena, this one taking place in the air. US fighter pilot Captain William Overstreet pursued a German plane over the city, and damaged the fighter's engine. The German pilot attempted to shake off his pursuer by flying close to the Eiffel tower, with some claiming they actually flew underneath it.* The plot didn't work though, and the Nazi plane crashed to the ground. The sight is said to have inspired the resistance fighters who saw it. A few weeks later, the Normandy landings (better known as D-Day) would begin the process of reclaiming France and the rest of Europe.