Came across this fellow while reading the Tobias Churton book "Occult Paris - The Lost Magic of the Belle Epoque." Found the following works:
Dark Hellespont , words of Judith Gautier (Paris 1845-1917)
Vilanelle , with Judith Gautier
Epiphany , Lyrics of Leconte de Lisle
The Merchant of Smiles , drama (Japanese play in 5 acts and 2 parts). Odeon Theater, Paris April 21, 1888, libretto by Judith Gautier and Pierre Loti
A tear of the devil . Mystery. Salle Barbaganzes, Paris jun1910, libretto after Théophile Gautier (Judith's father)
Musiques bizarres , Composed for the Universal Exhibitions of Paris 1890 and 1900, published in 2 volumes by Hartmann, Ollendorff, editors. 1889 and 1900
Sonata of Clair de Lune , opera (with Beethoven as hero), libretto Judith Gautier, for the Opera-Comique in 1903.
Doesn't seem to be a lot about him biography-wise out there...
There's this French Wikipedia page (https://fr.wikipedia.org/wiki/Louis_Benedictus) but I agree it's brief. Also this (http://composers-classical-music.com/b/BenedictusLouis.htm).
Thank you :)