David Sessions investigates why. Among other reasons:
[A]lmost all foreign-language television and many Hollywood films are dubbed, rather than subtitled, in France. The practice is driven both by popular demand and by the French state’s attempts to block invasion by foreign languages, especially English. While what the government calls the “cultural exception” —that French culture won’t be left to the ravages of the market—is certainly understandable, it can have unintended side effects, like insulating the French population from linguistic awareness they need in a world increasingly dominated by English.