Typically these bans are limited to the inner city or the historic center, there is - outside of some small towns in Switzerland - no major European city that I am aware of that has banned vehicles outright.

The towns that have banned vehicles completely that I am aware of are all small and have simply set up a major parking lot right next to the access road into town. For the ones that I am aware of this was a practical thing to do because the streets in winter were already more or less useless due to the snow and the inclined roads so it was a relatively minor step.

A nice example of such a town:

https://en.wikipedia.org/wiki/Saas-Fee

Pop. < 2000, car free since the 1950's.

Also, the greek island of Spetses https://en.m.wikipedia.org/wiki/Spetses

Spetses is not car-free per se. You can't bring your car on the island as a visitor - but people who live there can have a car (+ taxis & buses)

Of course, but cars are not allowed in the town of Spetses where almost all of the population of the island resides. I've been there before some years and it was great!

Taxis buses and other cars are used for transportation to remote areas of the island.

Islands are pretty good candidates to start this. We have a couple here in NL but the majority have vehicle access through ferries.