The baby boy was locked in after his mother parked the electric car in an underground garage. She and her friend got out of the vehicle and then closed the front doors.
However, when they tried to remove the sleeping baby from the back seat, they realised all the doors were now locked and the car key was still inside, Zurich police said in a statement.
Given the car was a Tesla, it should have been possible to open the vehicle with a wireless or mobile internet connection, but as the vehicle was in an underground car park this was not possible.
According to Swiss daily Blick, the woman was also unable to get through to the Tesla support hotline on the phone.
The mother of the child enlisted the help of the building caretaker and the pair spent an hour trying to break into the car using force with the help of everything from a fire extinguisher to a piece of garden furniture, but to no avail.
Eventually the police were called in. Officers then tried to open the car by smashing a window with an emergency hammer but only ended up breaking the hammer.
The broken emergency hammer. Photo: Zurich Police
Finally, they managed to force their way in to the Tesla using a crowbar.
Incredibly, the baby was still asleep having missed the whole drama and failing to wake even when the car's alarm went off during the break in.
Later on Tuesday, the woman told police the car was equipped with a form of “bulletproof glass” which she had not known about, Swiss media reported.