In Biggles Foreign Legionnaire, Sergeant Voudron was an orderly room sergeant in the French Foreign Legion training centre at Zebrit, Algiers. Also a member of the war-mongering syndicate, he took orders from the local senior syndicate member, Jules Raban who resided at the Villa Mimosa in the town of Zebrit.
Voudron's main role in the syndicate was to serve as talent spotter to identify potential recruits for the syndicate. As orderly room sergeant, he had access to the legionnaires' personal files and would scrutinise them for people with suitable profiles. When he noticed that Biggles and Ginger (who had joined the legion undercover) had aviation backgrounds, he began to pick on them and even planted rumours about them being sent to a particularly hard posting in a remote desert fort. All this was to incite them to desert. When Biggles and Ginger played along, Voudron sent them on to Raban who interviewed them before recruiting them into the syndicate.
When Marcel Brissac joined the legion undercover as a compnay commander, Voudron discovered his true identity by eavesdropping on his phone conversations with Captain Joudrier. Voudron later tried to organise Marcel's assassination by hiring a pair of killers from the souk in Zebrit but this effort was thwarted by Biggles and Ginger who spotted the assassins approaching Marcel. Voudron was arrested together with Raban towards the end of the book.