Citreon C3 Front wipers operate at times when ignition is switched on?

My daughter's C3 (02 model ) as a strange fault. the front wipers operate when the ignition is switched on and the wiper switch hasn't been touched. the wipers operate several sweeps of the screen before stopping in various positions on the screen. She has to operate the wiper switch to get the wiper blades to park in the correct postion. Any ideas anyone.