My assumption was that somehow, the Nazis make a separate truce with the British after crushing France (yes, extremely unlikely if not outright ASB, but I just made the assumption). The ideas given in the above link seem... implausible.
It took at least a year for Germany, using Czech factories in addition to its own, to jump-start tank production in preparation for the invasion of Poland. Once the Reich had the industrial power of all of Europe, it was deemed ready to take on the USSR.
In the given link, it would limit it to just Germany and whatever allies it could manage. Unless Poland and Romania are both on Germany's side, the invasion is going to be funneled through a very thin strip of East Prussia, something making it easier to contain.
Plus, in a bizarre twist, the Fall of France was what triggered the messy state the Soviet army was in right when Unternehmen: Barbarossa started. Stalin had organized his army along the lines of attrition warfare; masses of infantry, static defenses, and trenches, supported by tanks and artillery. Ever since the failure of Soviet maneuver warfare in taking Warsaw during the Soviet-Polish war of 1919-21, Stalin was convinced maneuver warfare was a passing fad, and set up his army to fight in WW1 style. When the defensively-oriented French Army was crushed by the offensively- and maneuver-oriented German army, there was suddenly this rush to switch everything over to maneuver warfare before the Germans overwhelmed them too. Had Stalin stuck to positional/attrition warfare, he might have had a better chance to fight off Barbarossa, or at least contain the damage from the early stages.