French doors can transform a space faster than almost anything. They are an excellent option for anyone looking to update a space without remodelling or expensive upgrades. 
French doors allow a lot of light through, effectively functioning as windows, allowing the light to flood your home. Replacing your windows with a set of French doors can be a wonderful way of letting an increased amount of light into your home and changing the overall atmosphere. If you want the versatility to have a small space turn into a giant space, these doors are perfect! And, when the weather is warm, you can simply open the doors to expand your living space and let  fresh air circulate through your home.

Ok, what was the question(s)?
Can you put fly screens on French doors? Or, can French doors have screens? How do you attach a screen door to a French door?
Of course you can put a fly screen on French doors. The best and versatile screen door for a French door is a retractable fly screen. 

Installing a retractable screen door is very simple, taking less time than you think.
There is no need for an extensive toolkit, most retractable screen door kits can be installed with an electric drill and an everyday tool selection.