Boëly was a vital link between the late Classical and early French Romantic schools, often incorporating Bachian counterpoint into his works. This Fantaisie is distinctive for its rigorous structural integrity and dark, driving energy.
At Henle 6 this is an advanced piece that assumes fluent technique and rewards mature interpretation. The main demands: independent voices that must each sing on their own line; fine finger independence within the hand; and precise articulation — the difference between crisp and blurred is the piece.
Beyond that, expect sharp dynamic and character contrasts held together in one arc.
Focus on maintaining crisp articulation during the dense contrapuntal sections.
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.
Fantaisie (Op.21) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 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 Fantaisie (Op.21) lasts about 7 minutes.
Fantaisie (Op.21) 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 Fantasia by Alexandre-Pierre-François Boëly, Fantasia and Fugue, C minor by Johann Sebastian Bach, Fantasia and Fugue in D minor by Johann Sebastian Bach — see the full similar-pieces list on this page.