What is French Seam? Where is it used? Why should your waist around 1 inch of fabric?
Above are the queries came to my mind when I learnt French Seam. So answers are given below.
French Seam is a double Seam which hides the raw seam inside them.(Step by Step French Seam Sewing)
It uses in a lightweight, sheer and delicate fabric.
How to Sew French Seam
SEWING STEPS
1
TAKE TWO PIECES (for practice first)

French Seam Sewing Step-1
2
Place fabric on each other from the wrong sides, Do a single seam(on front face of the fabric)

French Seam Sewing Step-2
3
Mark the 0.5 iNCH away from the Seam.

French Seam Sewing Step-3
4
Cut the marked area.

French Seam Sewing Step-4
5
Press the seam by opening it similar to below image.

French Seam Sewing Step-5
6
Look of Pressed Seam

French Seam Sewing Step-6
7
Revert the Fabric and Do seam, away from edge.

French Seam Sewing Step-7
8
Do press to one side, left or right anyone would work.

French Seam Sewing Step-8
FINAL LOOK:

French Seam Front and Back
FULL SEWING TUTORIAL:
Now your raw edges are no more exposed, as they are inside your newly made French seam