San Lorenzo market

I presume you are talking about the Central Market building.
Market on the ground floor is open Mon-Sat from 7am to 2pm. I think in certain months the Sat opening extends to 5pm.
Since April 2014 the market opened a new floor (first floor or 2nd floor to Americans) devoted to foods/restaurants. That part is open every day from 10am to Midnight.
The 'barrocci' (carts) in the streets open from 7am to 7pm i think daily, but not sure about Sundays.

The leather market is open seven days a week. I think the previous poster was refering to Mercado Centrale, the huge grocery/produce/meat market. There are tents/kiosks, and workshops in the San Lorenzo market, and I've never seen them closed! Maybe Roberto will chime in here as he's a native and I have only been a visitor (several times).

I shopped in the San Lorenzo market when I was in Florence a couple of weeks ago. At a couple of places I asked if they'd be open on Sunday and the answer was a firm "no." One of the places I went to gave me their business card. They have 2 leather stores with big stalls in front of them. the email is [email protected] - why not write and ask them.

Thanks for your replies. I did mean the leather market. I will try to contact the shop, as suggested to see what they say.

So sorry, I try never to give incorrect info! I never saw it closed both weeks I was there, but perhaps I was NOT there either of the Sundays!