phrase/fʁaz fe.tiʃ/
a sentence frequently employed by a person or character; a catch-phrase
“C'était la phrase fétiche, le mantra, que chacun répète, sans même s’en rendre compte, tout comme le chrétien répétait le « vade retro, satanas » pour se protéger de la tentation.” — It was the catch-phrase, the mantra, that everyone repeats, without even realising, just as the christian repeated "vada retro, satanas" in order to protect himself from temptation.
phrase + fétiche (literally, 'lucky phrase').