If you are looking for the translation of “phrase” in the sense of “a word or group of words that functions as a single unit in the syntax of a sentence, usually consisting of a head, or central word, and elaborating words” (definition taken from wiktionary), then it would be commonly called a “groupe”, but as it is a fairly vague term, it is often used with a more precise adjective or noun, eg “groupe sujet”, “groupe nominal”, “groupe verbal”, “groupe complément”, etc. A more precise term would be “syntagme”, but its usage would be limited to scholars and linguists (I cannot imagine it would be used in a classroom of a school).