Originally Posted by
jitkaau
Place wrong sides of two pieces of material together and sew a seam along the edge. Turn both pieces of material so that right sides are touching each other and press the seam directly along the sewn line. Then sew a slightly wider seam than the one before. so that you are encasing the previous seam's raw edges inside the new seam. Your French seam is now done.
Note to add: assuming you are using a regular sewing pattern with 5/8 inch seams, make your first seam 1/4 inch, and the second one 3/8 inch. The two will total the requisite 5/8".