The media first reported the idea to dispatch the Mistral to the Pacific almost s month ago, at the end of March. The French ship also has two British helicopters onboard.
The drill coincides with North Korea's latest failed missile test, but officials say the drills had been planned for some time.
"We did not expect the start of our visit to coincide with a North Korean missile launch," French Ambassador to Japan Thierry Dana said on the Mistral's bridge, according to RT.
"Cooperation between our four nations in upholding laws, peace and stability in the region will display our readiness to deal with North Korea," he added.
Both Japan and the United States are concerned about what they call China's efforts to extend its influence beyond its coastal waters and the South China Sea. France, which also owns several islands in the Pacific, shares these concerns to some degree.
However, Chinese maritime aspirations have been overshadowed by North Korea's repeated missile tests. US President Donald Trump ordered several US ships, including the USS Carl Vinson supercarrier, to move to demonstrate to North Korea the potential military consequences of its nuclear ambitions.
The Mistral is an amphibious carrier — a ship that carries amphibious armored vehicles for ground attack inside its hull. It can also carry helicopters and VTOL (vertical takeoff and landing) aircraft to support the littoral assault.