You get to keep the title, so a former mayor is called "Mayor" or "Mayor Smith." (By the way, never refer to a former mayor as "ex-mayor." "Ex" is only for spouses and convicts.)
ex-mayor
The former mayor of Bridgeport was P.T. Barnum.
"Your Honor" or "Mr. (Mrs.) Mayor"
Former mayor of Makassar
Mrs. Mayor
Mr. John Jones.
No. If the person is no longer holding that office, they revert to being simply Mr. or Mrs. (or counselor if they are still one).
The best way to address the mayor is to call him mayor with his last name. This will demonstrate that you are professional and you know what to call him or her.
There were many former mayors, but one was my grandfather, Ernesto Flores, mayor from 1970-1974, died of an enlarged heart in 1978
The 29th of February is the birthday of the former mayor of Dublin, Andrew Montague.
Andrew Young
a Mayor