Where can I find publicly accessible paternoster elevators?

You can visit three of them in Brno. They are at these locations:
1) Post office next to main train station (there is big sign POŠTA, you can’t miss it)
2) Faculty of Mechanical Engineering which is part of University of technology (address: Technická 2
616 00 Brno)
3) Brno city hall (address: Malinovského náměstí 3 (Malinovsky square 3))

Not sure if the one in the GrossMarkt Halle (in Ostend, Frankfurt am Main), now the ECB is still working and accessible. When I worked in the building (had an office there) I used to ride it everyday.

Vienna city hall,
active and publicly available Paternoster,
open from 06:30 a.m. thru 4 p.m. local time on working days.
North entrance #6 (Felderstrasse)

https://club.wien.at/magazin/lifestyle/paternoster-im-rathaus/

They celebrate its 100th birthday this year.

The government building in Copenhagen, Denmark has one; although I’m not aware of how many hoops you’d have to go through to obtain access.

Somebody posted this video from the Christiansborg elevators — I would not have filmed it in 90* rotation!

There is a fantastic website (albeit in German) called PatList that lists every paternoster elevator in existence, as well as whether or not its publicly accessible. Currently there’s about 300 such elevators left in operation (of which at least 50 are freely accessible to the public), so they’re far from rare. Google Translate works well with the site, so it should be easy to find places to visit.

Overall your best bet would be to travel to Germany and Czech Republic, as they have the bulk of the worlds remaining paternosters in operation. In fact I rode one this morning here in Prague 🙂

There are a few Paternosters still operating in Prague – the most accessible one is located in New City Hall, and there are others (I am not sure if they operate) in the buildings of CTU Campus.

Similar to Hilmar’s answer, the city hall of Stuttgart, Germany also has a Paternoster that is publicly accessible and frequently mentioned on TripAdvisor.

It was opened in 1956 and was temporarily shut down in 2015 due to legal issues. You can watch it being re-opened on YouTube.

You can visit the Paternoster during the opening hours of city hall, usually from 8am to 6pm on weekdays.

^{Image by РБМК-1500 from Wikipedia, CC BY-SA 3.0 DE}

Bochum in Germany has one in city hall that’s a local city favorite. It was closed in 2013 for legal reasons but re-opened in 2015 by the mayor herself.

She hits the button at around 1:50.

The paternoster at the Arts Tower in the University of Sheffield, UK (Universities web-page, BBC video) certainly used to be open to the public. These forum posts from 2012 and a number of more recent Tripadviser reviews suggest that this is still the case. The university also publishes a self guided tour (pdf) which includes the tower and its blurb does talk about the paternoster but also states that there is “Limited access to inside building”.

Alternatively you could book yourself onto a public event inside the building. Monday to Fridays 15th to the 29th of June an architectural exhibition is taking place in the arts tower. Or you can view their full list of events. The university has also traditionally opened one building up to members of the public to tour in September each year as part of the heritage open days scheme, the arts tower opened in 2012 and the university didn’t take part last year (2017). Weather or not they will take part in 2018 and which building will likely be known around mid July (Source). Obviously there is no guarantee that the paternoster will be running on any given day/time. But i’d image its most likely to be the case from around 9-5 during term time. The building does feature other normal lifts which may be in use instead – something which I would imagine is more likely going to be done for a late evening event or on a weekend/event out of term time. You could send an email and try and ask the exact opening times.

Finally, you could also visit on an open day with potential students, there are a handful of dates over the summer or the students union offer more regular tours to non-students. They note that “Although the campus tour will take you past most of the academic buildings, if you wish to visit a specific department and speak to a member of staff then you will need to contact them directly, at least two weeks prior to your visit to the University.” you could ask if there tour includes the Arts Tower, or ask if they would be willing to while you are there. While these tours are open to the public, they will of course be designed for prospective students of the university.