Here's why:
* Agreement with Nouns: "De" agrees in gender with the noun it precedes. For example:
* "La" (feminine) "fille" (feminine) "de" (feminine) "Paris" (feminine).
* "Le" (masculine) "garçon" (masculine) "de" (feminine) "Londres" (feminine).
* Exceptions: There are exceptions to the rule. "De" remains unchanged even if the noun following it is masculine. This happens when the noun is not directly preceded by a determiner (like "le", "la", "les"). For example: "Un homme de Paris" (a man from Paris), where "Paris" is masculine but "de" remains feminine.
Let me know if you'd like to explore other French grammar points!