Jean-Baptiste Alphonse Karr (24 November 1808 – 29 September 1890) was a French critic, journalist, and novelist.
Karr was born in Paris, and after being educated at the Collège Bourbon, became a teacher there. Some of his novels, including his first, Sous les Tilleuls (1832), were autobiographical romances. A second novel, Une heure trop tard, followed next year, and was succeeded by many other popular works. His Vendredi soir (1835) and Le Chemin le plus court (1836) continued the vein of autobiographical romance with which he had made his first success. Geneviève (1838) is one of his best stories, and his Voyage autour de mon jardin (1845) was deservedly popular. Others were Feu Bressier (1848), and Fort en thème (1853), which had some influence in stimulating educational reform.
In 1839 Alphonse Karr became editor of Le Figaro, to which he had been a constant contributor; and he also started a monthly journal, Les Guêpes, of a keenly satirical tone, a publication which brought him the reputation of a somewhat bitter wit. His epigrams are frequently quoted, for example "plus ça change, plus c'est la même chose"—"the more it changes, the more it's the same thing", usually translated as "the more things change, the more they stay the same," (Les Guêpes, January 1849). On the proposal to abolish capital punishment, "je veux bien que messieurs les assassins commencent"—"let the gentlemen who do the murders take the first step".
In 1848 he founded Le Journal. In 1855 he went to live at Nice, where he indulged his predilections for floriculture, and gave his name to more than one new variety, notably the dahlia (New International Encyclopedia). Indeed he practically founded the trade in cut flowers on the French Riviera. He was also devoted to fishing, and in Les Soirées de Sainte-Adresse (1853) and Au bord de la mer (1860) he made use of his experiences. His reminiscences, Livre de bord, were published in 1879–1880. He died at Saint-Raphaël (Var).