France has the most time zones of any country when its overseas territories are included. It uses 12 different standard time zones, or 13 if France’s Antarctic claim is counted.
The reason is geography rather than the size of metropolitan France. French territory stretches across the Atlantic, Pacific and Indian oceans, including French Polynesia, New Caledonia, Réunion, Mayotte, French Guiana, Guadeloupe, Martinique and Saint Pierre and Miquelon. These territories lie at widely separated longitudes.
Metropolitan France itself uses only one standard time zone, Central European Time, with Central European Summer Time during the European daylight-saving period. The overseas territories generally keep their own local standards, and most do not change clocks seasonally.
The United States and Australia are common alternatives because each spans a large mainland and has island territories. Russia also crosses many longitudes, but France’s worldwide territorial spread gives it the larger total under the usual country-and-territories count. The number can vary slightly depending on whether Antarctica is included, which explains the 12-versus-13 wording.