In 1858, when the Philippines was a Spanish colony, France and Spain invaded Vietnam. A number of French troops involved in this campaign became casualties as a result of contracting illnesses such as cholera, dysentery, tropical diseases, and rickets. In order to deal with the manpower shortage which resulted from this situation, the French consul in Manila, the colonial capital of the Philippines, was given permission by the Spanish government to recruit nine hundred Indians, as Filipinos were then known, for the French navy and a sufficient number of men to form an infantry company and a cavalry squadron. It is said that one-third of the entire French force in this campaign consisted of mercenaries from the Philippines, who distinguished themselves in action and were well adapted to the environment.
There were twenty-three Filipino mercenaries who served in the French Foreign Legion from 1914 through 1918. The legionaries from the Philippines, by that time an American colony, constituted the largest number of legionaries from the region which years later would be known as Southeast Asia. Other legionaries from the region who served in the Legion during World War I were: four Cambodians; two Dutch Hindus; ten Indo-Chinese; two Siamese; and four Tonkinese. Also during the European War, which is how Filipinos referred to the Great War, Dr. Basilio Valdes, a University of Santo Tomas graduate and a University of the Philippines instructor, served in the French medical corps. He was appointed Assistant Surgeon at the no. 101 temporary hospital at Avenue de la Republique in Paris, and worked at the Necker Hospital. The following awards which he received made him the most decorated Filipino of World War One: Croix de Chevalier de la Légion d'honneur, Médaille de la Reconnaissance française, Médaille d'honneur, Médaille de la Grande Guerre, and Médaille de la Victoire. After the war Valdes would serve in the American colonial gendarmerie and later the American colonial army and would become its chief of staff. He would also become defense secretary of the colony. The Filipinos in French service during this war outnumbered the Filipinos who served the colonial master as members of the American Expeditionary Force.
A number of Filipinos presently serve in the French foreign legion.