Wheelchair rental Florence

I don't, because when I did need a wheelchair for my mother I bought it. However, there should be a free wheelchair service by the Florence municipality, based at the info office at Piazza Stazione 4 (on the back of SMN church). Wheelchair have to be reserved in advance at touristinfo@comune.fi.it , a deposit is paid, you get it back when you take back the chair. Try writing them and check if the service really works.

If not, try moveris.it, they will deliver the chair at your hotel and they offer also electric scooters.

An alternative if needed: my brother used this product when travelling with his wife who had mobility problems (though she could handle a couple of stairs if needed) and he reported it fully met their need and was easy to fold and carry.
https://www.amazon.com/dp/B002VWK3IY/?coliid=I1AN3I0QDHFX14&colid=VP7AIY8DE7NE&psc=1&ref=listcwllvovligdpit

The Florence tourism website has the following information:

https://www.feelflorence.it/en/dalle-redazioni/getting-around-barrier-free

Wheelchair users: Florence city centre as well as many other historical cities, can present some objective difficulties for visitors with reduced mobility: moving from one place of interest to another it is not always so easy (in the oldest part of the city sometimes the sidewalks are narrow and the surfaces of both streets and sidewalks can be uneven).
So, to avoid architectural barriers, it may be useful to consult Kimap, the App that shows disabled people paths. App download: Apple Store, Google Play.

If you want to discover the city download also Passepartour (4 itineraries in the historic centre, fully accessible for wheelchair users) at the following link.

Wheelchairs free rental: At the infopoint of Piazza Stazione 4, you can use this service for free, leaving a deposit. Service on request: tel. 055 212245 / touristinfo@comune.fi.it. At the infopoint, publications about accessibility are also available.