What happens to China if France doesn't fall in 1940?

  Difficult to tell but the KMT should be better off.  There's no Japanese occupation of FIC so not a threat from that border and it and if necessary Burma can continue to be used for aid from the western powers.  - If Japan still goes to war with the west that could change but since they would have to attack FIC 1st their unlikely to successfully invade Malaya and the DEI.  Especially if by that time Nazi Germany was largely defeated.

  With a stronger western bloc opposed to Japanese invasion of China then Japan probably runs out of funds and possibly other resources at some point in the early/mid 40's.  Which would force them to either strike south, although that would be an even more desperate move than OTL, come to some agreement with the Chinese or be forced to withdraw, probably keeping Manchuria but no more.

  As such your more likely to have the KMT stay the dominant power in China and it might defeat the CCP, at least in terms of denying them a territorial position.  However the communists are still likely to be a continued guerilla threat and probably also somewhat of a terrorist one while the KMT, without the desperation of isolation on Taiwan its likely that the KMT would stay pretty much corrupt and dominated by powerful vested interests.  As such its unlikely to suffer things like Mao's Great Leap Forward and Cultural revolution but may not have the economic success of OTL Taiwan and later mainland China.  Also it would have tensions with the Japanese empire and quite probably the Soviets over disputed borders.