At the outbreak of World War II, although married with two children, Biéler joined the Canadian Army in Le Regiment de Maisonneuve and was shipped to a base in Britain. His wife Marguerite Geymonat worked as a broadcaster to the troops in Europe on Radio Canada International. Because of his familiarity with France and his fluency in the French and English languages he joined the Special Operations Executive in 1942. Known by his wartime nickname "Guy," or his code name "Commandant Guy", following his specialised training at Camp X, Colonel Maurice Buckmaster, the SOE commander, wrote in his file that Biéler was the best student SOE had.
Operations in France
On 18 November 1942, Biéler, along with wireless operatorArthur Staggs and Michael Trotobas, were parachuted into France. Unfortunately, in the darkof the night, Biéler severely injured his back after landing on rocks and he spent several months recovering. He had strong communication and organizational skills, and as the head of the Musician Network he was able to work with fellow SOE agents and members of the French Resistance to organise very productive sabotage missions. Operating from a base in Saint-Quentin in the northern Aisnedépartement, Biéler's twenty-five teams, scattered over different areas of northern France, were successful in damaging or destroying German gasoline storage tanks, rail lines, bridges, canal locks, and the electric tractors used to tow barges on the shipping waterways. Their repeated efforts hampered the movement of enemy arms and troops but the most important job for Biéler would eventually be the preparations for D-Day. His daughter Jacqueline Bieler researched "Commandant Guy's" life extensively, for her book Out of Night and Fog and provided the following summary of his escapades in France to the CBC: His operations were so successful that the Germans instituted a special manhunt to get him and his team and on 13 January 1944 the Gestapo arrested him and agent Yolande Beekman in the Café Moulin Brulé in Saint-Quentin. At the Gestapo headquarters there the two were tortured repeatedly but never broke and a few months later Biéler was transferred to Flossenbürg concentration camp in the Oberpfalz region of Bavaria, where the brutal torture continued. According to his daughter Jacqueline Bieler's research, prisoners at Flossenburg were called Nacht und Nebel,. "When you were designated an NN prisoner, you were meant to disappear. If the Red Cross asked questions about you, they weren't supposed to find out anything." Unable to get useful information from him, the Germans executed Major Guy Biéler by a firing squad – instead of the gas chamber or piano wire often used on other agents – with a guard of honour, on 5 September 1944. "It proves even the Germans could not but recognize his great qualities," according to then-Colonel Maurice Buckmaster, the SOE commander who added that Biéler had been the best student SOE ever had.
France: Croix de Guerre In Saint-Quentin, France, he was adopted by the citizens as a folk hero not only for his exploits and bravery but also because he was someone who did everything possible to avoid civilian casualties.
Monuments
The "Rue du Commandant Guy Biéler" in Saint-Quentin was named after him.
As one of the SOE agents who died for the liberation of France, he is listed on the "Roll of Honour" on the Valençay SOE Memorial in the town of Valençay, in the Indredépartement.
There are memorials honouring Bieler at Morcourt, and Fonsommes
On 22 July 2007 an exhibit on Bieler was unveiled at the opening of the museum in commemoration of all those who suffered and died at the Flossenbürg Camp at Flossenbürg, KZ, Germany.