Riviera Maison Biarritz Placemat The Biarritz line consists of products made from dark-dyed seagrass, a beautiful, natural material that lends itself to various applications. The Biarritz Placemat is a large placemat with a diameter of 36 centimeters, so you can easily put a plate, plate and glassware on it to put together your perfectly set table.