Connecting a phone to the car via Bluetooth automatically

It is possible to connect a phone to the car automatically via Bluetooth. The phone has to have been connected to the car for the first time.
It is only the two last connected phones that can be connected automatically.

Activate Bluetooth in the phone before setting the car in ignition position I.

To connect the car to the Internet at the same time, tethering (portable/personal hotspot) in the phone must be activated.

Set the car in ignition position I or higher.
The phone will connect.