Section 715.07 http://www.leg.state.fl.us/statutes/index.cfm?mode=View%20Statutes&SubMenu=1&App_mode=Display_Statute&Search_String=715.07&URL=0700-0799/0715/Sections/0715.07.html of Florida Statutes “Vehicles or vessels parked on private property; towing” provides the regulations. If the property is not a single family home or if you haven’t personally notified the vehicle owner, you have to have a proper tow away sign in order to tow.
You have to use a commercial towing company.
A business owner or lessee may authorize the removal of a vehicle or vessel by a towing company when the vehicle or vessel is parked in such a manner that restricts the normal operation of business; and if a vehicle or vessel parked on a public right-of-way obstructs access to a private driveway the owner, lessee, or agent may have the vehicle or vessel removed by a towing company upon signing an order that the vehicle or vessel be removed without a posted tow-away zone sign.
The vehicle’s owner can stop the tow by paying up to one half of the towing fee and has the right to inspect the vehicle before accepting its return.
To prove that the vehicle was parked improperly, take a picture of it.