A young girl was attacked and bitten by a dog while on the beach opposite Les Grandes Maisons Road.
The dog is believed to have been a Border Collie type.
Its owner is described as a white woman in her early 40s. She had brown hair, spoke with a French accent and was wearing a pink jumper at the time.
Officers are wanting to speak to anyone who witnesses the attack, which happened on Saturday 5 June.
An appeal has just been issued.
Anyone with information are asked to contact Guernsey Police or Crimestoppers anonymously on 0800 555 111.

Artwork exhibition celebrates Guernsey architecture
From Guernsey office to Windsor Castle: Doug Perkins gets CBE
Aurigny promises average Guernsey-Jersey air fare will be £70 one way
A Channel Islands success story to expands to Dubai
First electric buses arrive in Guernsey marking the start of fleet transformation
Channel Islands could get a third of monthly rainfall in 24 hours
Channel Islands Air Search plane "temporarily unavailable" due to registration issue
People with chainsaws told to keep out of Le Guet on Guernsey's west coast