France was defeated rather brutally in 1940 and suffered greatly in the next 5 years.

After the war there were between 10,000 and 50,000 executions of collaborators. This includes everything from 'legal' government trials against the top people to street lynchings and shootings.

One thing you must absolutely understand is the situation for French citizens and soldiers between 1940 and 1944 was a changing shade of grey, not the black and white that we see today where obviously one would not fight for Vichy France and obviously one would be in the Free French/Resistance.

The Free French are celebrated today, the city I live in has several monuments, plaques, street names etc dedicated to the soldiers/resistance/civilian victims and this is very normal for French cities. Today collabo is a huge insult in France and while people are aware of the degree of collaborating it is not a great subject to bring up. The French, like countries, prefer to focus on the ‘positive’ aspects of their history. Thus in general, collaboration is quickly dealt with: it sucked and those people were jerks but it wasn’t my family they were in the resistance like everyone else is typical of the reaction one gets.

Between the French surrender (June 1940) and the allied landings in North Africa (Operation Torch Novembre 1942) l'Armée d'armistice was allowed several hundred thousand soldiers, the majority in French colonies and 120,000 in métropole/mainland France. The idea was that France was neutral since Vichy was the legit government of France and had signed a treaty ending the war.

The soldiers in the Vichy Army were, likely all soldiers, trained to obey orders. Many of them fought against allied landings in Africa and then changed sides later. Obviously individual soldiers could make individual decisions, and many mid ranking officers were willing to join the Free French early on, but the importance of the generals was great.

De Gaulle was a général de brigade and thus outranked by many other soldiers who were in France when the treaty was signed. Look at the message De Gaulle sent to higher ranking general Charles Noguès the day after his famous appeal to the French.

Suis à Londres en contact officieux et direct avec le gouvernement. Me tiens à votre disposition soit pour combattre sous vos ordres, soit pour toute démarche qui pourrait vous paraître utile. <

In English

Am in London in informal and direct contact with the government. Hold at your disposal either to fight under your orders, or for any step that may seem useful to you.<

Maxime Weygand, who replaced Maurice Gamelin as head of the French military during the battle of France, continued to serve in the French military until nearly 1942. He convinced Noguès to accept l'Armistice, as Weygand was higher ranking, and not to go with De Gaulle. Mittelhauser and most of the other top brass holdouts went along with Weygand/Vichy. Most of the French troops saved at Dunkirk elected to return to France and not to join De Gaulle.

There are two issues here. One, why people would be collabos and two, how they were treated after the war.

People collaborated for a number of reasons which make perfect sense when you think about it. Some nationalists believed collaboration was the best way to protect France and French interests. Many people just wanted to survive and believed collaboration was the best way to do this. Others believed they could profit from collaboration. Some Vichy soldiers were already in the military, conscription was abolished for France proper but pay was increased. Outside of France many Vichy troops were colonial troops, I’m not sure of the exact numbers but there were something like 200,000 Vichy troops in Africa, I have no idea how many of these would have been of European origin but I imagine a minority. These African based units went over en-mass to the Allies after Operation Torch.

The Vichy Army was dissolved by Hitlers orders on 26 November 1942 when France lost its semblance of neutrality and Germany full occupied the country. Many Vichy officers had been stockpiling weapons etc and hated the Germans but were not Gaullist either.

Everything I have read leads me to believe that there was a cleansing directly after the war with many people not caught up in the first round, Maurice Papon being a prime example, continuing with their lives. These were, in theory, not people who had tried to get by but people who had profited or committed crimes. How much that occurred in practise is hard to say since the textbook says between 10,000 and 50,000 which is a huge number.

The Vichy troops and also those from Alsace-Lorraine were absolutely not seen the same way as the SS Charlemagne or the Milice française. That being said they were also not seen as heros like the Resistance and Free French. They were in a middle ground along with the French soldiers who had been interned for years during the war. Not something to be proud of, unless you did something specific to aid the war effort, but not something to be ashamed of either.

I'm basing this answer mostly from 1945-1947: La France de De Gaulle(1988) but also from the high school textbook LE MONDE d'aujourd'hui (1972) which I chose since large number of Vichy veterans would have still been alive when it was a published. There is also a very good, fictional, tv show un village francais, of which I have only seen the 1st season, about the occupation.

As a rider to this question, was sentiment markedly different based on what branch of the military they served in?