The French knot is a stitch which is great for adding raised texture. You can change the size of the knots depending on your thread and how many times you loop it round the needle to add variation into your work.
The French knot is quite simple to do but can be a little bit fiddley. To start with you pull the needle up through the fabric. You the go to point your needle to go back through the fabric close to where you just pulled it up through. Before you push it back down you wrap the thread around the tip of the needle twice. Then hold the thread to one side and push the needle through the fabric. The thread should knot creating a French Knot.
Here is an example where I used this stitch.

