Mailliet competed as a lone female swimmer for Luxembourg in the 200 m freestyle at the 2008 Summer Olympics in Beijing. Leading up to the Games, she smashed a Luxembourgish record in 2:02.71 to clear the FINA B-cut (2:03.50) by nearly a second at the Open Luxembourg Nationals in Luxembourg City. Swimming on the outside in heat two, Mailliet raced her way to sixth place with a steady 2:02.91, just two tenths of a second (0.2) shy off her entry time. Mailliet failed to advance to the semifinals, as she placed thirty-ninth overall in the prelims.