According to
Liszt's letters to Princess Carolyne zu Sayn-Wittgenstein, Tintamarro was Liszt's nickname for Carolyne zu Sayn-Wittgenstein.
My French is rather limited, but I believe that Liszt gave her that nickname to tease her for her preference for what he considered pompous and loud music.
(Since my French isn't that great, I asked,
Roger64, who is a native French speaker, to double-check this theory for me.)