Yeah, they make it rather tricky getting the hatch open. An inside latch release would have made sense.
What year/model? Did the hatch handle break, or is it the switch? You'll need to get the hatch open before beginning a repair. The vids will make it easier. On that first one, I'd suggest using a trim tool to remove the factory trim cover clips, instead of just yanking the cover off. There are several threads on both sites on causes. For early models, it could be the hatch wiring harness, on later models is the switch or (in one case) a connector.
^^^^^As map posted above. I posted 3 opening solutions above. On another forum. Common issues to this model. What is up with Fiat? It could be the micro switch, or the hatch wiring. It’s easy to pull that back inside panel off. Then open the hatch, per those videos.
It's probably either the switch in the hatch handle, or the wiring between the hatch and the body. I had both problems myself at different times. The piece of harness between the hatch and the body is a real liability on high-mileage cars.
I was unable to open the hatch with the screwdriver prying method shown on the video on either of my 2012 Pops. After a LOT of exploring I found a recessed lever on the face of the hatch latch that does the trick. Lift it up with the screwdriver and it unlatches easily.