At the 2006 European Championships in Budapest, Steffen clocked 53.30 in the women's 100 m freestyle event, breaking the world record and upstaging the previous record of 53.42 set by Libby Lenton of Australia. Even though Lenton swam a time of 52.99 on 4 April 2007 during the mixed 400 metre freestyle relay, this time was not recognized by the FINA as world record, because the race is not considered to be a FINA event.