Philatelists (and fans of the Audrey Hepburn-Cary Grant 1963 thriller Charade) will want to head to Paris's unique stamp market at the intersection of avenue Marigny and avenue Gabriel overlooking the gardens at the bottom of the Champs-Élysées. On sale are vintage postcards and stamps from all over the world. It is open Thursday, weekends, and public holidays from 10 until 5. Métro: Champs-Élysées-Clemenceau.