Beep Beep Beep to the Brake Pressure

In my 2004 307 1.6 xt vehicle, when I press the brake, it is not always, but there is a digital warning sound. Beep beep beeps three times in the form of beeps and the car gives this warning again, depending on the head, even if it does not do the next brake.

I did some research but I couldn't find a clear answer. Does anyone know? I do not know what to do as there is no fault light or fault information on the screen.