It also completely goes completely opposite from my own experience, which is that on average the Japanese people I know are more literate in their language than the French people I know are literate in theirs (including myself). That sure is anecdata, but it's about as much anecdata as the OP.

Edit: I should mention that I live in a "relatively" small city in Japan (180k inhabitants), that many qualify as "inaka" (countryside), although I wouldn't. So the population of Japanese people I know is not necessarily biased towards highly educated people.