Perfectly normal in France, you can still find racists obviously, like anywhere else, but half people ("métisse") are usual and normal.
Yeah, in Japan it's weird. Some people will find half beautiful and classy and be jealous, others will hate them. In any case, they're not considered normal, and most people will behave in a weird way with them. But Japanese society is deeply racist, and it won't change soon unfortunately. I would say that now at least, there is less stigma about marrying a foreigner, but it might depend on the parents. My girlfriend's parents are perfectly happy about me, and another of their daughters is dating a Brazilian guy. But on an other hand, other old people sometimes say to me "your girlfriend doesn't look exactly Japanese, so obviously she's not Japanese, don't lie about it", even though she maybe has origins outside of the Tokyo area (like south Japan on one side), but is entirely Japanese. If you don't look like the average local, then you're a foreigner, and even a stranger, and they can be very weird and insulting about it.
Other thing that made it a lot harder for the girls in the OP: they're half black. Japanese people are racists toward white people but still consider them beautiful (almost like a superior race for some people), but they're a lot worse about black people. Like "lower race" worse. Same thing usually with Vietnamese people or other Asian countries, Japanese treat them like garbage sometimes. I guess for them a half-white would be beautiful and classy, a half-black would be an inferior being. I even met a half Japanese/Vietnamese girl who looked very Japanese to me, but she told me she was annoyed by Japanese people regularly...
By the way, it's "haafu", with a long "a" :P (end of the "Yeah, I know some Japanese, how classy" moment)