This is one of the episodes during the Ricardos' trip to Europe. After leaving England they travel to France, before moving on to Switzerland and Italy. In "Lucy Meets Charles Boyer", Boyer guest stars as himself and Lucy gives him the same treatment she gave the stars in Hollywood.
This is one of those Europe episodes that are a little underrated. Everyone knows "Lucy's Italian Movie" (aka Lucy Stomps Grapes), but there were other episodes during the Europe trip that are worthy of attention as well. Lucy coaching "Maurice DuBois" (Boyer) on how to act like Charles Boyer is a highlight of the episode.