Hi there !

Do you know wich template is using this website ?
http://www.studiofmmilano.it/FM/projects/

thank you very much

It is some custom theme. It's not a theme you can download via the Zenphoto site.
Maybe ask the owner of the site.

For sure a custom theme not available generally. Even if it was it would not really work as the site uses an really ancient Zenphoto version.

Do you know something similar ?

With a horizontal browsing ?

No, all known freely available themes for Zenphoto are listed here: http://www.zenphoto.org/theme/