This detail is more about how I treated a piece of lace rather than embellished a seam.
Stitches:
On the edge of the lace I have used 3 straight stitches arranged in a fan like shape. At the base of the shape I stitched a small bead.
Thread:
DMC perle thread #5.
Placement and Foundation Fabric:
The lace is on a seam which is between piece 3 and piece 7. You can find the the diagram of the block in the post I wrote when I introduced block 6 In the same article I also explained what foundation fabrics I used.
Lace:
This lace was received in swap.
Beads:
The lace was decorated with seed beads