After the 1951–1955 fifteen volume and the 1960 twenty-four volume collected works of Balzac came out, translations from these editions have been reprinted many times, both in new collected works and in stand-alone volumes, yet their quality has never been questioned. These translations are still perfectly readable, but upon comparing them to the originals it turns out that more than once the original has been either misinterpreted or considerably watered down. This article demonstrates mistakes and/or elements lost in translation of several works, namely The Wild Ass's Skin, Melmoth Reconciled, History of the Thirteen, The Illustrious Gaudissart, The Splendors and Miseries of Courtesans, Father Goriot. These mistakes mainly stem from insufficient knowledge of the historical and cultural background of the Balzacian era. It is due to unfamiliarity with the contexts that houses' walls turn into Parisian outskirts, a jester with a drum is replaced by a mattress and a shed, and Seraphin, the puppet theatre owner, turns into a seraph. In other cases, the realia important for Balzac himself and his contemporaries, such as palingenesia, incredibly popular and on-trend in the late 1820s — early 1830s, or the mules of Don Miguel, that refer both to historical and to literary events, are simply omitted — which makes the translation smoother but less historically accurate. In the mid-20th century, translators lacked our access to Web search and to textual and culturological commentaries by French scholars specializing in Balzac, which is why we have no right to blame them for such mistakes. But noticing those and doing our best to suggest more correct variants is both desirable and necessary.