Accorder ses violons, literally “to tune one’s violins”, means to compromise, to adjust in order to reach an agreement. The closest expression in English is “to get your stories straight”. The idiom dates back to the 19th century. At that time, un accordeur de flûtes (“a flutes’ tuner”) was the slang word for a magistrate. By extension accorder ses vielles (“to tune one’s viols”) and accorder ses violons were used along with accorder ses flûtes when an agreement had to be made between two people.