De Gaulle and treason:
1. When he fled to England he was doing so with large numbers of French soldiers, which was an ally during a war, with the intention of continuing the war which was government policy at the time. Not treason.
It depends on whether you accept that he did not know that Petain was going for an armistic when he (deGaulle) left for England.
If you accept that de Gaulle did know, then he left the country in an 'hour of need' to be at the side of a soon-to-be non longer ally with the intention of sabotaging the peace talks.
2. When he made the appeal on the 18th the French were still at war with the Germans. His appeal was to continue that war. Not treason.
It would be interesting to know whether subordinate French commanders are usually expected and allowed to officially contradict government policy, or if we assume he did not know, express their opinion in times of war.
I doubt it.
3. After the armistice on June 22nd he continued fighting. This is a clear cut case of de Gaulle disobeying the legitimate instructions of the legitimate government. Whether that is actually treason is debatable but it is certainly illegal.
Treason is defined in the laws of the 3rd republic, among other things as 'putting French troops under the authority of a foreign government'.
It is hard to argue that de Gaulle did not do exactly that.
4. After Petain assumes dictatorial powers on the 10th of July. The argument can be made that the Vichy regime is not legitimate due to some irregularities in the process of the 3rd republic dissolving itself. As such de Gaulle could legitimately argue that it was not the government of France.
Difficult. But sure, discussing the minutiae of the self-dissolution of the 3rd Republic probably leads to far here. Just because Vichy is illegitamte does not mean de gaulle is legitimate though.
Clearly, continuing fighting after your government has agreed to stop is major problem from a military commander. Imagine if an American commander attempted such a thing - breaking an armistice to continue fighting at their own discretion! It is the basis of all democracies that the civilian government is in charge and gets to make the decisions about when and where to fight wars and when and how to end them and military commanders must obey their instructions.
It goes even farther.
France was no longer able to conventionally resist Germany in the Metropolitan area. They needed an armistice.
If de Gaulle had gotten his wish and caused widespread guerilla activity and completly delegitimized the government there would have been no armistice, there would have been no peace and instead there would have been guerilla warfare, which means killing collaborateures, razing villages, shooting hostages, etc. By 1944 France would have been a wasteland.
This is not to make excuses for the Vichy regime, who were fairly evil, even by the low standards of the 1930s and 40s. It is simply to say that de Gaulle's decision to fight on was not a legal decision for him to make. Only with the establishment of the Vichy regime was his leadership of the Free French in any way legitimate.
I disagree. While the Vichy Regime got quite evil, there not evil from the start... they slowly eviled up.
And this sliding scale makes it so interesting, at least to me, to think about when Free France becomes the France.
Of course the British didn't care about the legalities of de Gaulle's actions, they simply wanted someone to rally French forces against the Nazis. In the end the Free French became the government of France because when asked the question "you and who's army?" they could simply point to the hundreds of thousands of guys with guns marching through France.
This had an interesting knock-on effect though. There had been a long-standing policy that 'rebel governments' were not legitimate.
The Rif rebellion had died because despite being the 'legitimate' government by League of Nation standards, they were a rebel government and therefore not to be negotiated with.
The whole decolonization process sped up quite a lot and cost Britain quite a bit of power because post-war everybody felt free to embrace whatever government would sell them the most mineral rights.
A lot of the precendent for the shit-shows in Africa, South America and Asia were laid by the financing and legitimization of European resistance movements by the Brits and later the Americans, who ironically would then face their biggest defeat in a war against resistance movement very similar to the French Resistance.
@Keynes:
Becoming a Nazi-ally as such does not de-legitimize a government. It is a very important part of international politics to be able to do things others do not like without losing legitimicy