Bonjour Chris ! This is case 5 in the lesson: "Adjectives modified by adverbs with 2 or more syllables". Here "beau" was nuanced by the adverb "vraiment" (really beautiful), so they go together, and because "vraiment" is a 2-syllable adverb, therefore the group adv+adj is placed after the noun. I hope that's helpful! À bientôt !