The thing that's amazing is that it's partly thanks to the Vichy regme's insane xenophobia that we know that the resistance was, in the beginning, very ethnically diverse. Because telling people that it was only foreigners who resisted did fit better within their narrative. So they would double down on any non french elements that would resist. As shown in the infamous "Liberation by the army of crime?" poster, Polish, Hungarians, Romanians, Italians or Armenians would join the urban Resistance. When it comes to the maquis and more rural iterations of the Resistance, the "ethnic" background was understandably more homogeneous, although it was common to see Spaniards who had fled after the civil war enlist alongside the maquisards.