The Americans certainly didn't succeed on D-Day alone. It took a concerted effort from all the Allies. And the French Resistance, which had been fighting the Germans since the occupation of their country, helped out plenty, too. In this article, Warlord Games takes a look at some of that help and how it'll work in the upcoming D-Day: US Sector book for Bolt Action.
From the article:
Veteran Jedburgh teams supported the French resistance during the Allied invasion in 1944 - find new rules in the forthcoming Campaign D-Day: US Sector!
There were several resistance movements throughout occupied Europe. With their ability to disrupt German communications and movements from behind enemy lines, they were a critical resource to the coming invasion. Their members were also at high risk of being captured and killed. The Allied high command realized that without help, many of these groups would eventually fade out. To keep this from happening, a joint operation between the US, Britain and France called ‘Jedburgh’ was formed.
The mission was to parachute small teams of specially trained commandos behind enemy lines. These teams would assist the guerrilla fighters by training them and arranging supply drops. The radios they carried provided a crucial link between the guerrilla resistance and the Allies. It was a dangerous mission, made all the more hazardous by the fact that they often fought in uniform as opposed to sneaking in disguise. The men chosen for this duty had to be proven veterans and were then put through a rigorous training process to make sure only the best made it to a team.