These 'bouquets' by Cramer feature melodic arrangements drawn from Offenbach's 'La princesse de Trébizonde'. This style of transcription was immensely popular for piano enthusiasts, making operetta tunes widely available.
Maintain a delicate and sparkling touch, suitable for the lighthearted operetta music.
2 Bouquets de mélodies sur 'La princesse de Trébizonde' is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
2 Bouquets de mélodies sur 'La princesse de Trébizonde' is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.