The Allies had invaded southern France on August 15, 1944 for a number of reasons, but they are complicated and I will not try to explain them here.
Lieutenant Swank was part of a small party parachuted into the area as the Germans retreated. The Germans had invaded Vichy France shortly after the D-Day landings. According to local legend, Swank and his co-Lieutenant had planned an ambush along the road in this narrow river canyon, intending to block the German retreat and attack the convoy. The Germans, expecting an attack, and being the ruthless bastards they were, took hostages from the nearby town of Couiza, (citizens who volunteered under pressure knowing they would probably die, and if they didn’t volunteer knew the entire village would die) and strapped them to the roofs of their vehicles, intending to frustrate or stop an ambush. Rightly undeterred, Swank descended to the level of the road and attacked from there, hoping to kill Germans not hostages but exposing himself and losing his life in the process. Reportedly, Lieutenant Swank had said he wanted to be buried where he died, wherever that happened to be.
He was buried nearby but the US Army insisted on bringing the body home, as is the custom in most cases. The family later disinterred Swank from his resting place in the States and re-interred him in Alet-les-Bains.
The entire story and the report on the mission in which Swank lost his life can be found at this website. http://www.languedoc-france.info/1016_ww2.htm
I recommend you go there and learn all about Swank and his mission. Please scroll down or read as far as "Operation Peg" for a history of the mission itself.
There are slightly different translations between the French and English versions on the marble plaque. Below are the texts on the opposite sides of the monument:
HERE FELL FOR THE CAUSE OF FREEDOM AND LIBERTY
LIEUTENANT PAUL SWANK ARMY OF THE UNITED STATES
AUGUST 17 1944
AND LIES HERE ACCORDING TO HIS OWN WILL
ICI EST TOMBE GLORIEUSEMENT POUR LA LIBERATION DE LA FRANCE
LE LIEUTENANT AMERICAN PAUL SWANK
17 AOUT 1944
ET Y REPOSE SELON SA VOLUNTE