In Biggles Works It Out, Emile was an operative of Count Heinrich Horndorf's criminal gang known as "The White Prophets of Peace" based at the oasis of El Asile. Originally a member of the French Foreign Legion, he had deserted when he heard that his mother was ill. His mother died before he got home. The police was waiting for him and so he ran off again and got picked up and recruited by the gang. By the time he met Bertie, who had penetrated the gang posing as a pilot named "Smith", Emile had become tired of his life at the oasis and talked often with Bertie about wanting to escape.
When Algy piloted the gang's Douglas DC-3 to El Asile, posing as yet another new pilot, he arranged to escape with Bertie. They took off just as a Mosquito bearing Groot and von Stalhein arrived. By this time, von Stalhein knew that Bertie and Algy for who they really were and opened fire at the DC-3 as it was on its take-off run.
Algy got off successfully but soon heard a voice shouting from the cabin. It turned out to be Emile, who had stolen on board. He had come forward to warn them that von Stalhein's bullets had punctured the fuel tank and they were losing fuel badly.
Algy, Bertie and Emile force-landed in the desert about 10 miles away from El Asile and were soon surrounded by Tuareg tribesmen. Emile, who spoke some of the Tuareg language, discovered that they were on their way to raid El Asile. Algy, through Emile, pleaded with them to leave El Asile to the French authorities but to no avail and the three were taken prisoner and forced to accompany the Tuareg raiders but were released after the raid in time to join Biggles and Marcel and Captain Joudrier, who had arrived with a large force of French gendarmes to mop up.
At the end of the book, no charges were brought against Emile because of his good behaviour and help to Algy and Bertie. He had to rejoin his regiment but, through the influence of Captain Joudrier and Biggles, Emile was able to opt for training as a pilot in the French Air Force. Upon completion of his pilot training, Emile was posted to North Africa.