Jacques-Albert Anschütz's '2 Bouquets de mélodies sur 'Jean de Nivelle'' are likely arrangements of melodies from the opera 'Jean de Nivelle' for piano. These pieces would showcase popular tunes with accompanying keyboard figurations.
Focus on bringing out the melodic lines clearly and supporting them with tasteful accompaniment.
2 Bouquets de mélodies sur 'Jean de Nivelle' is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 4.
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 2 Bouquets de mélodies sur 'Jean de Nivelle' lasts about 4 minutes.
2 Bouquets de mélodies sur 'Jean de Nivelle' is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.