Here are a couple of the books I used to remind me of the stitch. This first is French. The actual stitch is made from the back of the fabric.
And this one is Polish.
Here is the finished piece from the back. I made the stitches on the front very exact (straight down two threads) but I was less concerned about the back and these stitches come out mostly two stitches down but sometimes three and sometimes over one or two to the side. When you are stitching a hem, you have to watch both sides.
