This piece is a salon-style fantasy based on themes from Giuseppe Verdi's Requiem, transcribed for the piano in the style of 19th-century operatic paraphrases. It transforms solemn liturgical themes into a decorative and lyrical display piece typical of Henri Cramer's prolific output.
The primary challenge is balancing the operatic melodic lines against the florid, ornamental accompaniments typical of salon music.
Comparable difficulty and character — good candidates for what to learn next.
Bouquet de mélodies sur 'Requiem' de Verdi is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 6.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Bouquet de mélodies sur 'Requiem' de Verdi lasts about 6 minutes.
Bouquet de mélodies sur 'Requiem' de Verdi is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Bouquet de mélodies sur 'Les contes de Perrault' by Cramer - Pseudonym, Bouquet de mélodies sur 'Les cent vierges' by Cramer - Pseudonym, Bouquet de mélodies sur 'Le roi de carreau' by Cramer - Pseudonym — see the full similar-pieces list on this page.