Police said the man approached a 27-year-old woman from behind in the 1800 block of San Pablo Avenue at about 2:10 p.m. on Tuesday.
Police said the man grabbed her and began dragging her backward while touching her in an inappropriate manner.
However, the woman struggled and was able to get away and call police, according to authorities.
Police only have a vague description of the suspect at this time, as they don't know his race. They say he is between the ages of 25 and 35 and is 5-foot-4 and 160 pounds with black hair and was wearing a gray shirt, a black vest and gray sweat pants during the incident.
Crime Stoppers of Oakland is offering a reward of up to $5,000 for information leading to an arrest of the suspect.
Oakland police said anyone with information about the incident should call their youth and family services division at (510) 238-3641, their tip line at (510) 637-0298 or Crime Stoppers of Oakland's tip line at (510) 777-8572.