Constant beeping

[A15gpk]

I own a C300 amg prem plus, yesterday my wife got into the car turned on the ignition and a beeping sound appeared from around the control for the lights. It’s almost as though someone has got a Casio digital watch and the alarm is going off. No warning lights on dash and no messages. I’ve put new batteries in both keys and tried but it’s still going what could it be??