Franz Mezger's work is typical of the transition between the late Classical and early Romantic styles. It utilizes conventional harmonic patterns and clean, balanced phrasing.
At Henle 3 this is a late-beginner piece — comfortable hands-together playing is assumed, and musical shaping starts to matter. The main demands: Alberti-bass accompaniment kept quiet and even under the melody; precise articulation — the difference between crisp and blurred is the piece; and fine finger independence within the hand.
Pay close attention to the steady control of alberti-bass figures in the left hand.
Comparable difficulty and character — good candidates for what to learn next.
A level or two down with the same spirit — ideal if this piece is still out of reach.
Where this piece's skills lead: slightly harder works making similar technical demands.
Lesser-known works by the same hand, at a comparable level.
Divertissement No.3 in D major is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 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 Divertissement No.3 in D major lasts about 4 minutes.
Divertissement No.3 in D major 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 Divertissement No.2 in F major by Franz Mezger, The Entertainer by Scott Joplin, Waltz No. 2 by Dmitri Shostakovich — see the full similar-pieces list on this page.