Maybe something like this; no Entente Cordiale. World War I breaks out similarly to OTL, but France instead of Germany violates Belgian neutrality first, and ultimately the main powers are the Entente of France, Italy, Russia, and Turkey and the Central Powers of Austria-Hungary, Bulgaria, Germany, Japan, and the United Kingdom. While forced itself to defend it's metropole against the Russians, Japan also plays a pivotal role in the Pacific and Indian Ocean theaters. After the war, an equivalent to the League of Nations is set up, and in the horse trading of French colonies after the war, Japan is ultimately made the mandatory power over some of France's Indian Ocean islands colonies; Comoros, Madagascar, Réunion Island, or some combination of the above. Madagascar seems like a bit of a stretch in my opinion though.