As such, there is no beach, swimming was prohibited. But there are places to relax, sunbathe, and sit in the company. But the water is unusual, you can take original photos if you find a location without people and typical "non-southern" vegetation)
A good place to relax on a trip around the Brest region in good weather. The beach was clean and well maintained, the water was cool, the entrance was clay, you have to be careful not to slip. There are comfortable, covered gazebos with a table and benches and a place to light your own barbecue. The barbecue is allowed in the specified location. There is convenient parking. Also, the beach and quarry are under video surveillance and if someone violates the rules, a vigilant man right there with a megaphone will warn you very loudly and unexpectedly for you.
Locals call this place "Maldives" because of the blue color of the water. The water is blue, because the lake was formed on the site of a former chalk quarry. The beach is quite official, equipped, you can swim without fear.