After the collapse of the Second French Empire, the Third French Republic banished any and all heirs to the many monarchies that once ruled the country. This included all branches of the houses of Orléans, Bourbon, and Bonaparte.
The now defunct-royal families lived in exile and their power waned with each passing generation. Years passed and family lines continued, leading to the birth of the great grand-nephew of Napoleon I, Louis Napoleon VI. Following the death of his father, Louis became the Bonapartist claimant to the French throne at age 12 while living with his mother in Switzerland. He lived a fairly quiet life and a 1929 recording of him shows a love for film.
When World War II broke out in 1939, he immediately wrote to the French Prime Minister, Édouard Daladier, asking him to overlook the nineteenth-century law and allow him to fight in the French Army. He was denied. Not satisfied with watching his homeland burn, he joined the French Foreign Legion under the pseudonym "Louis Blanchard." According to Legionnaire tradition, recruits enlist under a nom de guerre, or war name, to let go of who they were before they enlisted and restart their lives.
Related: 7 reasons the Night's Watch is basically the French Foreign Legion
Louis fought in North Africa with the Legionnaires until the Second Armistice of Compiegne. The armistice was all but in name a French "surrender" to Nazi Germany and the death of the Third Republic. His unit was demobilized in 1941 under the order of Vichy France. However, his fight wasn't over. He planned to make his way to London to join de Gaulle's Free French Forces, but was captured by German border patrol en route in December 1942.
Eventually, he would escape his cell and join the French Resistance, this time under another pseudonym, "Louis Monnier," just before the Normandy invasion. He served in the Brigade Charles Martel, a subtle armed resistance that fought alongside the Allies. He joined them in pushing back the German forces until Aug. 28, when his seven-man patrol was obliterated. He lived but was severely wounded. He was transferred to the Alpine Division, where he adopted a third nom de guerre, "Louis de Montfort," and continued the fight.
He would earn many awards for his actions in WWII, including the title of Commander of the Legion of Honor, the highest French award — one created by his great grand-uncle — for his actions. Louis Napoleon VI would live out his life in Paris, despite authorities knowing it was illegal, until the law was repealed in 1950. He would spend the rest of his life as a prominent businessman and a powerful figure in many historical associations until his passing on May 3rd, 1997.