How Babel Fish almost caused a diplomatic incident

You probably know that the Babel fish, in Douglas Adams’ The Hitchhiker’s Guide to the Galaxy, is a species of fish which, when put into someone’s ear, allows the "wearer" to communicate in any language. Further than that, the Babel fish is itself a reference to the biblical story of the Tower of Babel, built by humanity at a time when everyone spoke the same language.
*Sentence obtained by asking Babel Fish to translate "You’d be better off hiring a professional translator" in French (You’d soit meilleur outre de louer un traducteur professionnel ), then to translate this sentence back into English.