A French oven is the name for a large pot used for cooking and baking. This pot can be fairly large and round, with a flat bottom and often comes with a tight fitting lid. Though different pots of this type can have different kinds of handles, they usually either have a thick wire handle that is connected to two sides and can swivel over the pot or hang to the side, or two smaller handles on opposite sides of the pot. A French oven is usually made from cast iron, though it is not unusual for the iron to be coated in enamel or made from ceramic instead.
Typically called a Dutch oven, “French oven” is simply a term that has traditionally been used by several French manufacturers of these types of pots. Dutch ovens have been around for hundreds of years and continue to be used even with modern technology. They were originally designed to be able to cook over an open fire, and many of the features that made these ovens so popular 300 years ago continue to make them popular today. A French oven can be heated on a stove top over high heat and be transitioned into or out of a hot oven all in the course of a single preparation.
Much like a Dutch oven, a French oven is usually made from cast iron and can then be either coated with enamel or left uncoated. When uncoated, it will typically need to be seasoned and cared for just like any other type of cast iron cookware. Cast iron should not be washed with soap or detergent, and should only be cleaned off using hot water and a metal brush. Soaps and detergents can damage cast iron cookware, and this includes an uncoated French oven.
Cast iron also typically needs to be seasoned, which means it should be treated with oil before being used, and then be treated again after every cleaning. A French oven that is properly cleaned and treated can quite literally last a century and still be usable. After sufficient use and proper treatment the inside of this sort of cast iron pot will typically become nonstick to a remarkable degree. The nature of iron, however, is such that acidic foods should not usually be prepared in them, since the acidity can react with the iron.
This is why a French oven will often be coated with enamel over the cast iron body of the pot. The oven will still be able to conduct heat effectively, but does not need to be seasoned, can be washed with soap, and will not react with any foods. High heat can potentially damage the enamel coating of this kind of pot, however, so they may not be suitable for use in deep frying with hot oil. Some of these pots can also be made using ceramic rather than cast iron and enamel, though these are typically not as sturdy as their metal counterparts.