If you overspeed on a road with an identified speed limit, the car will give you a warning of this by a sound of an alert along with a flashing speed limit symbol. The alert stops once you slow down.

You can replace the warning sound with adaptive pedal response. It helps you follow the speed limit by limiting the vehicle's propulsion. A harder press on the accelerator temporarily deactivates the function. The function might feel unfamiliar at first, try it out carefully.

Can this be deactivated? And if so, how?

You can’t deactivate ISA since this is a requirement regulated by EU law. This means that you either have to use the sound alert or the adaptive pedal response.

However, you can deactivate it temporarily by pressing the left-hand side steering wheel button. The alarm will then turn off for the rest of the trip. Meaning the next time you start the car it will be activated again.