The child is believed to have been assaulted in Thames Path, Thamesmead, on June 24 last year between 5pm and 6pm.
Police have released an E-FIT (Electronic Facial Identification Technique) of a man officers would like to speak to in connection with the incident.
The render shows a visualisation of a black male, however the Metropolitan Police have not provided further description of him.
Anyone who recognises the man is asked to call police on 101, quoting reference 3837/12Nov24.
