Bach's '10 Pièces favories et Concert italien' are not a standard collection, but likely refer to selections of his shorter works and the Italian Concerto. These pieces exemplify Baroque contrapuntal mastery and melodic clarity, showcasing intricate polyphony and harmonic invention.
Developing clear voicing and independent hand movement in contrapuntal passages is paramount.
10 Pièces favories et Concert italien is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 7.
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 10 Pièces favories et Concert italien lasts about 30 minutes.
10 Pièces favories et Concert italien is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.