Quoting Steve Cushion in On Strike Against the Nazis, page 46:

By 1943, the losses on the Eastern front resulted in [the Fascist bourgeoisie] deciding to implement a programme of forced recruitment of labour from France to compensate for their lack of manpower in [Axis] industry. This measure would have unintended detrimental effects on the [Axis] war effort.

The Service du Travail Obligatoire (STO), started in February 1943, was the organisation set up by the Vichy government to organise the dispatch of forced labour from France to [the Third Reich]. Some 600,000 French workers were sent to [the Third Reich] in 1943 and 1944. Another 200,000 managed to evade the round‐up and these young men formed the basis for the massive increase in the rural resistance.

This round‐up and deportation to what was essentially [neo]slave labour, initially enforced by the French Police and Gendarmerie and later aided by French fascist paramilitaries, such as the Milice and Parti populaire français, (PPF, French Popular Party) as well as the [Wehrmacht], was massively unpopular and may be seen as an important turning point in alienating French public opinion from the Vichy government of Maréchal Pétain.

There was a severe shortage of labour in the country as a million and a half French soldiers were still being held in [Axis] POW camps. The réfractaires, as those fleeing the STO were called, were sheltered in rural areas in return for their labour on farms and it was a natural step to supporting them as they took to the hills and forests when the Vichy authorities came looking for them. In turn it was logical for these réfractaires to arm themselves against the forces of repression. They then quickly turned from defence to attack, from being the hunted to the hunters.

In some ways, the existence of the rural resistance can be seen as a form of large scale collective action, a form of community civil disobedience.⁹⁰ The [Axis] authorities certainly saw the situation as a rural revolt and treated the peasants in the villages with extreme brutality. There was a general policy of burning villages and massacring civilians in areas of strong Maquis activity in an attempt to terrorise the base of support of the guerrilla bands.

This growth of a rural guerrilla movement was also an opportunity for the hard‐pressed urban terrorist networks to send at least some of their fighters into the hills to train and lead these groups of militarily inexperienced young men.

(Emphasis added.)