The names Thomas Carlyle (1795–1881) and Eugène Sue (1804–1857) rarely figure in the same sentence. Carlyle is commonly remembered as a dour Scots Calvinist and eminent Victorian; Sue, in contrast, as a sensational French novelist, and sybarite-turned-champagne-socialist. Nevertheless, the following article will contend that Carlyle was in fact familiar with the works of Sue, to such an extent that he adapted passages from the latter's Mystères de Paris (1842–1843) in his own Latter-Day Pamphlets (1850). First, the article will offer a brief sketch of Sue and his novel, before discussing their reception amongst Carlyle's circle of friends and acquaintances. It will then suggest that Carlyle himself was likely to have read the novel, and then proceed to compare the relevant passages of the Mystères and the Pamphlets, which together constitute the primary focus of the article. Finally, it will be argued that this matter is far from being a mere curiosity, of concern only to the most obsessive of Carlyle scholars. To the contrary, it will be suggested that in understanding what Carlyle did with Sue, we will be better able to grasp the meaning of some of the more notorious passages of his most notorious work, and particularly their political thrust. In doing so, the article will build upon a number of recent studies of the reception of French literature in Victorian Britain, and will also reopen the question of Carlyle's debts to French socialism, an issue that continues to be a matter of some controversy amongst Carlyle scholars.