Achille Leonardi's signature is very distinctive and painted in red. He generally included the address of his studio.
There are some paintings attributed to him which are not in fact his work. This can usually be seen in the signature.
This website was established to consolidate as much information about the 19th century Italian artist Achille Leonardi as possible into one place. If you have a work of Achille Leonardi, I would very much appreciate information about it and a photo or two. You may email me at firstname.lastname@example.org .