Here's a link to an article in a Belgian newspaper about the fact that Mathilde is wearing a lot of DvF these days.
Gazet van Antwerpen – online krant
It says that since Diane von Furstenberg's sister in law opened a DvF store in Brussels, Mathilde is seen a lot in her creations. She goes to the store and discusses there what suits her best. Because the clothes are so recognisable, people go to the store afterwards because they want the same jacket or dress Mathilde wore.