The sculpture Armonía (Harmony) was created by Edith Berlin, an accomplished sculptor from Veracruz, in 1994. It was located at the intersection of Calle Genova and Calle Liverpool – in the heart of Mexico City, but seems to have been moved after 2015 or so. map
Berlin has created other mermaid sculptures and is well known for these.
The mermaid is shown with a rose in her hair and a conch shell in her left hand, cresting a wave with two dolphins leaping out of the water with her.
References:
● https://libertadbajopalabra.com/2019/10/09/edith-berlin-un-suspiro-veracruzano/
● The Mermaids of Earth coffee-table book: See page 148 in the book about this sculpture.