Final answer:
Marshal Philippe Petain was initially revered as a World War I hero but became a controversial figure for leading the Vichy government that collaborated with Nazi Germany during World War II. Post-war, his popularity diminished significantly due to his government's actions, leaving a tarnished legacy.
Step-by-step explanation:
The popularity of Marshal Philippe Petain varied over time. Initially heralded as the 'Hero of Verdun' for his leadership during World War I, Petain became the Prime Minister of a truncated French government based in Vichy after the fall of France to German forces in June 1940. This Vichy government, although nominally independent, ended up collaborating with Germany.
Many in France, particularly on the right, supported the collaboration as they had lost faith in democracy and preferred partnership with Germany, thinking it might protect their interests in a German-dominated Europe. However, this acceptance was also due in part to the influence of German propaganda. The Vichy regime sought to reorganize France along authoritarian and fascist lines, which subsequently sparked resistance both from within France and from French nationals abroad, including General Charles de Gaulle who opposed the Nazi-accommodating regime from exile.
After the war, opinions on Petain were overwhelmingly negative due to his government's collaboration with the Nazis and its repercussions. Petain was viewed unfavorably for the role he played in the persecution and deportation of Jews, among other wartime activities. His legacy has since been marred by his association with the Vichy regime and its collaborationist policies.