Originally Posted by
CPH-Flyer
Which is probably because JAL can charge a higher price for that X class in connection with a HND-CDG-HND booking than they can for a CDG-HND-CDG booking
Probably, so.
But, in this case, we can purchase CDG-HND-CDG X class (same price in France) at TA in Japan, or JAL in Japan, even JAL France site doesn't have X class availability.
So, restricting X class in French POS assumes not so many people in France are calling Japan for ticketing :-)
Then, back to topic.
When you couldn't find availability in JL site in China, still you may try TA, or JAL in your own country.