A common assumption (also eagerly made by yours truly) is that a CP victory TL (hereby defined for the sake of this discussion to be caused at least by Italy in the CPs and USA out of the war) is going to produce a rather more utopian 20th century than OTL. The CPs becoming socialdemocratic liberal constitutional monarchies, creating an early EU, no Hitler, perhaps no or a contained Lenin-Stalin, the stuff. Another common assumption is that France and/or Russia are going to switch nasty, seek a rematch and cause a *WWII. Well, I was wondering, if all of this be the case, how much of OTL 1930s-1940s bad stuff would we really miss ?
Let's assume that indeed things for the CPs go as good as usually assumed. Nonetheless, at some point Russia somehow remains/swings Red/Brown, and France somehow swings Brown (I deem Communist or too early a blatant revanchist France too unlikely, the CPs would intervene and crush it in the bud). The CPs sleep at the helm, and the nasty duo, in an alliance of opportunist convenience with imperialist militarist Japan, unleash WWII. How much of the OTL WWII atrocities would be avoided, and how much would still happen, perhaps with different victims, in this scenario ?
Moreover, let's assume that the CPs still end up victorious in the rematch, perhaps with some serious Anglo assistance (hereby assumed that Britain would have got a lenient peace, so it would have made its peace with the CP hegemony soon after WWI), perhaps on their own efforts alone. What kind of "1945" harsh peace would France and Russia get ?