No one, expert or amateur, will come and remove this old ac from a long-gone previous occupant. It’s easily accessible and I will pay a premium but no one in the Nice area will come because they’re scared of the Freon exploding.
I can’t help with your problem but think there may be some confusion, perhaps on my part…
Freon is not a flammable material it us unlikely to explode. The problem may be that as an old system it is using R22 Freon, or a similar environmentally harmful product. It should not be released into the atmosphere. The gas is usually under a lot of pressure, which could be their concern. If it should rupture a pipe the Freon will be released.
Perhaps you could approach this as 2 separate tasks. The first one being to drain off the old refrigerant, then the second is to remove an unpressurised non-functioning AC unit. Any AC company should be able to empty the unit, even cut the pipes so that is obviously no longer under pressure.
I have noticed that there is a tendency to specialise,e.g. Installing an AC unit the AC specialist will want an existing and suitable electrical supply point but will expect an electrician to connect it.