As Japan often manages to get Indochina from France through their focus tree while the Sino-Japanese War is still going on, how about adding a similar event like with Korea?

If you actually manage to occupy Japanese Indochina before kicking them out of China completely, you could get an event where you either take over Indochina for yourself, release it (either the three core countries or some newly-created union state) as independent or as a puppet or hand it back to France.

What do you think?