In 2019, Karen was invited to design a cobranded collection for the French department store, Monoprix. The collection comprised of homeware, baby clothing, children's clothing, womenswear, stationery and Christmas decorations. It featured around 130 items and was stocked in stores across the country.

In addition, Karen was invited to design bespoke windows for five of the brand's key stores in Paris, including the iconic Champs-Élysées.