French doors are full length doors that feature lots of small windows and for this reason are also sometimes referred to as French windows. The amount of windows mean that they provide little privacy so French doors are mainly used for decorative reasons or to provide maximum light enter the house, for example between a room in the house and a conservatory. French doors usually combine two doors and are assembled using multiple pieces of glass. It is common for the structural elements between the glass to be decorative to add to the appearance of the overall door.
As well as solely for decorative reasons there are also a number of other reasons why people choose these kinds of doors. As well as the above mentioned reason of allowing plenty of natural light into the house, French doors can help to draw focus to your garden. If you are a proud gardener and spent plenty of time getting your fingers green, then having a view of your work from the house is a great benefit. They can also make a good bridge between the inside and outside and allow you to seamlessly have the benefits of both.
Although they can be slightly more expensive than other types of doors, they are a good investment because they are considered to add to the appearance of the property and could increase the value of your home if you were to sell.
Out of curiosity, I wonder what French doors are called in France?
For French Doors in Kent and Surrey, try South Coast Windows.