Despite her best efforts, Zahia Dehar is still best known in France as a footballer's birthday present. The 20-year-old surprise new muse and protege of the fashion designer Karl Lagerfeld was not long ago a teenage, underaged prostitute who met clients in VIP bars around Paris's Champs-Elysées while her mother apparently thought she was at sleepovers with schoolfriends, and was paid for sex by one of France's most famous football stars.