The electrical current in France is 220 volts, 50 cycles alternating current (AC). French electrical outlets have two round holes, a "female" and a "male" ground; your appliances must either have a slender, two-prong plug that bypasses that ground, or a plug with two round prongs and a hole.
Consider buying a universal adapter, which has several types of plugs in one lightweight, compact unit. Most laptops and mobile phone chargers are dual voltage (i.e., they operate equally well on 110 and 220 volts), so require only an adapter. These days the same is often true of small appliances, such as hair dryers. Always check labels and manufacturer instructions to be sure. Don't use 110-volt outlets marked " for shavers only" for high-wattage appliances such as hair-dryers.
Steve Kropla's Help for World Travelers. The site has information on electrical and telephone plugs around the world. www.kropla.com.