Robert Jambon, 86, shot himself on the steps of the Monument Indochine in the Breton town of Dinan on October 27, police said, and in a suicide letter published by the newspaper Ouest France, he described his act as a protest.
"After a long period of disappointment, I have decided to play my final card, or more precisely my final bullet," he wrote in the letter, a copy of which was posted on the daily's website.
In the note, he said the suicide was aimed at expressing his shame and “to protest against the cowardly indifference of our officials in the face of the terrible misfortune that is hitting our friends in Laos.”
"This is not a suicide but an act of war aimed at rescuing our brothers-in-arms facing death," he continued.
Jambon, who fought alongside Hmongs during France's 1950-54 war in Indochina (the French name for a territory that now includes its former colony Vietnam) had spent decades trying to raise awareness of the minority's treatment.
The Hmong ethnic group lives mainly in mountainous areas in China, Vietnam and Laos. Many Hmong joined French forces during the war in Indochina and later fought alongside US forces in the Vietnam War during the 1960s and 1970s.
They have faced widespread persecution and Jambon had raised particular concern over the French government's reaction to Thailand's forced return in 2009 of thousands of ethnic Hmong asylum-seekers to Laos.