She was walking along Leavesden Road near the junction with Acme Road with her young son, when she was approached by a man outside the Chrysalis Dental Practice.
The man said “oh how beautiful you are” and then inappropriately touched her before continuing walking.
The woman in her 40s shouted at the man and chased after him, while he continued walking.
The assault occured between 2pm and 2.30pm on Monday, January 7th.
Detective Constable Jonathan Holmes, from the Watford Local Crime Unit said: “Incidents of this nature are very concerning and I am keen to speak to anyone who may have witnessed this incident. The suspect ran away down Leavesden Road toward St Albans Road. He is described as chubby, late 20s to early 30s and he was wearing a parker jacket.
“I am keen to speak to anyone who may have driven along Leavedsen Road between these times, especially those drivers who may have recordings on dash cameras in their cars. To the person responsible; I urge you to hand yourself in at the nearest police station to explain your actions.”
Anyone with information or any witnesses are asked to contact DC Holmes by emailing or the non-emergency number 101, quoting crime reference 41/2065/19.