On the masonite website it shows their standard sizes for interior french doors to be 12 16 18 or larger.
Normal size for french doors patio.
One door and one fixed pane suggest a pair.
Place the hinged side where the swing is most convenient.
Single slider courtesy of pella.
These doors are popular because they allow some privacy while allowing a visual connection between two spaces.
If you are choosing the two panel keep in mind that the standard width is 5 feet or 60 inches.
But just like how no home is the same no door is quite the same either.
You will find the two and three panel patio door configurations which have different widths.
Patio french doors often open on to a deck or a backyard patio and may be used with a screen door system.
The standard size of a patio door with a 2 panel configuration is 6 8 x 6.
The standard height of a patio door is 80 inches 6 feet 8 inches.
Taller bottom rails give single panes french door cred.
However i would not recommend a full glass door at the top of a stairs.
French doors are used as both entry patio doors and as interior doors that separate two spaces.
You would need 2 15 s or a tad smaller for your space.
200 series hinged patio doors in vinyl clad wood.
When you said french doors i assumed that you wanted them with glass since that is what a french door is.
A slider saves space indoors and out.