Is it possible to register in the city hall?

Yes, it is. In The Netherlands, you can always register in the City Hall, but only if you have proof of permanent residency with a BSN number, so you can avoid paying city tax. All you have to do is send us your official proof of registry. If you apply for a temporary residency and do not receive a BSN number, city tax will be applied.
In Barcelona, you can register at the Oficina de Atención al Ciudadano (Citizen Advice Office).
In Germany, you can register in the City Hall at any time, however city tax will still be applied. To avoid paying city tax, you should provide proof at the reception that your stay is related to business or educational purposes.
In Vienna, you can register at the Residence Registration Service Centre (Meldeservicestelle).
In Florence, all you need to bring at check-in is your passport. Guests from outside of the EU that are planning a stay longer than 90 days should go to the City Hall to obtain the mandatory “Permesso di Soggiorno” and to the Consolato for the VISA. You can only avoid paying city tax if you are studying at Università di Firenze or if you are in Florence for medical reasons.
For more information, we advise you to check the official City Hall website of your selected city.