Mottet started with track and field (athletics), but when she was 18 years old she switched to road cycling. Her specialty was competing in time trials. She represented France in junior events at the 2012 European Road Championships in Goes and at the 2012 UCI Road World Championships in Valkenburg. At the European Championships she finished fourth in the junior time trial. At the World Championships' women's junior time trial she finished 6th. During the women's junior road race she had a very bad crash. She got medical attention. Her father was with her as he was an UCI-official at the race. She suffered major injuries to her nose; complications arose and she never fully recovered. Next year, in the 2013 season she rode the 2013 Trofeo Alfredo Binda-Comune di Cittiglio World Cup race but did not finish. She also participated in the 2013 Cholet Pays de Loire Dames race and finished 53rd. Her comeback in 2014 was not possible. She started working as a massage therapist, remaining connected to sports.