That french seam is similar to the blue jean seam. Where you make one side deep enough to fold over the other side. It is basically the same seam only one edge is trimmed close to the seam the other edge is then folded over then topstitched. If she made two long seams strategically placed to follow along either edge of the bed it would give the spread a more tailored look.
I made a spread similar once. I didn't have enough fabric for a Queen size, so I attached a pleated bed skirt to the edge all the way around. I used gray and white pillow ticking and quilted an old mattress pad to the back. I attached the pleated skirt reverse fabric to reverse fabric and then trimmed the seam with home made bias tape in a contrasting color. The pleated skirt was a light weight broad-cloth in pale grey to match the grey in the main spread. It took an evening or two to finish it and I also made a couple pillow shams trimmed with the same green bias tape. The last time I washed it though I treated it with oxyclean and left it sit over night, I did not know that stuff would bleach fabric. So I plan to recycle it for use in the camper. It's time for a new cover anyway which of course will be a new quilt specially made my me:D