In an art gallery or art book, there’s a “label” alongside each piece that holds the information about the artwork like name of the artist, date, genre, …
Does this label has a specific word in English?
I think that “artwork label” or just “label” is the most appropriate word. I found an example of that usage on a “Practical Art World” blog. I have also found “wall tag” as an alternative. I don’t like it as well as “label” because it presumes it’s on the wall next to the artwork, like in the image of a “label holder”.
Even in that article that uses “wall tag”, the term “label” is also used:
“Sculpture labels are printed using the same clear labels. We use folded cardstock to display the labels on pedestals.”
The label might also be able to be described other ways (as a plaque, for example) but that describes its appearance more than its function. “Label” is unambiguous.
There are also engraved “fine art nameplates” (or just “nameplates”) that are attached to the frame of a work that just has the name of the work and the artist.