Compare the plug shapes, voltage and frequency in Japan and France, and find out which adapter you need before you travel.
Adapter required
Yes — coming from Japan, you will need a travel adapter for France. Japan uses Type A/Type B plugs, and France uses Type C/Type E, so the pin shapes will not fit any wall socket. Voltages differ (100 V at home vs 230 V abroad), so check the label on each device. Most modern dual-voltage chargers handle the swing without a converter, but heating appliances usually do not.
Japan (home)
France (destination)
Electrical specifications in France
More about plugs in France
In France, the standard power plug is Type C and Type E. The country runs on 230 volts at 50 Hz. That means wall sockets in France can be one of 2 different shapes — Type C, Type E, and your plug needs to physically match the socket to fit.
Full France plug guide