5th Foreign Infantry Regiment The 5th Foreign Infantry Regiment ( ) was an infantry regiment of the French Foreign Legion . It was based in French Indo - China and existed from 1930 to 1945 and again from 1949 to 1955 . History . The creation of the 5th Foreign Infantry Regiment was mandated on July 17 , 1930 to deal with growing disorder in French Indochina . The Regiment was established from the 1st , 7th and 9th Battalions of the 1st Foreign Infantry Regiment that had been previously deployed to Indochina from 1920 to 1927 . The 5th Foreign Infantry Regiment was tasked with reinforcing the troops already guarding the Tokin region . The 5th REI was deployed across northern Indochina with its headquarters located in the Red River delta . Garrison duty in French Indochina proved to be a fairly comfortable assignment for its legionnaires until the outbreak of World War II with the notable exception of the Yen Bei uprising in 1930 . World War II . After the Battle of France and Second Armistice at Compiègne , French Indochina remained loyal to the Vichy government , leaving the 5th Foreign Infantry Regiment largely on its own for the duration of World War II . On September 22 , 1940 the 2nd Battalion of 5th Foreign Infantry Regiment was attacked by elements of the Japanese 5th Infantry Division as they withdrew from China across the Tonkin border . The 2nd Battalion alongside the 1st Battalion of the 3rd Regiment Tirailleurs Tonkinois and the 1st Battalion of the 3rd Colonial Infantry Regiment put up a defense , but despite their efforts found themselves surrounded and without artillery , armor , or air support three days later and were forced to surrender . By September 26 fighting in the region died down and with the exception of repulsing the Thai incursion into Indochina , the next few years the 5th REI ' s military activity was limited to combating groups of armed bandits . On March 9 , 1945 , the Japanese launched a coup against the French leading to the collapse of the French government in Indochina . A French garrison consisting of more than 100 legionnaires at the fort at Brière de l ' Isle was surprised when it was attacked by a Japanese regiment , but was able to effect a defense through the night until its ammunition was exhausted by the next morning ; the Japanese massacred the French prisoners . Another Legion garrison was overrun at Ha Giang on the Claire River . Brigadier General Marcel Alessandri rallied as many elements of the 5th REI as he could outside of Vietri as he determined that the 5th REI was vastly outnumbered French forces had no choice but to escape the region as he had 2 , 000 legionnaires at his disposal compared to 40 , 000 Japanese soldiers in the region . General Alessandri decided that the only feasible escape was north to territory controlled by Nationalist China . Over the next fifty - three days General Alessandri led the 5th REI through mountainous jungle and heavy combat towards the Chinese border into Yunnan . Once on the other side the 5th REI still had to march another to Tsao - pa to receive help from the Nationalists on June 15 . On July 1 , 1945 , the 5th Foreign Infantry Regiment was disbanded . First Indochina War . On November 1 , 1949 the 5th Foreign Infantry Regiment was reestablished in the Tonkin Region of Indochina .