Prada, AW14, Milan.
Example of topstitching from the Autumn-Winter 2014 collection at Prada. In the example, topstitching has been used on the sleeve seam as well as on the patch pocket. In this example the topstitching appears to be both functional and decorative.
Notice that the topstitching here has been sewn as a twin stitch, with two lines of stitching running parallel. A thicker thread and longer stitch length are also sometimes used for topstitching to make the threads more prominent.
Images from Vogue.co.uk»