Éphémères translates to "ephemeral," meaning lasting for a very short time. It's a beautiful and somewhat poetic word that isn't heard in everyday conversation, making it quite memorable.
In the song, Mélanie Laurent sings about building "châteaux de sable dans la mousse, éphémères et pas droits" (sandcastles in the moss, ephemeral and not straight). This word perfectly captures the fleeting nature of these childhood games and, by extension, the passage of time while waiting for someone.
Have you ever been waiting for someone so long that time seems to stretch and bend? In "En T'attendant," which means "While Waiting for You," Mélanie Laurent captures this feeling perfectly. The song is a beautiful list of all the whimsical, childlike, and sometimes lonely things she does to pass the time. She describes winking at clouds, building crooked sandcastles, and making smoke rings with her cigarettes. These aren't grand actions; she calls them "childish games" that are "worthless," but they are her way of coping with the slow passage of time.
The chorus reveals the heart of the song: while time seems to be having a good time, she feels like she's losing or bored with her own. All these small, imaginative activities are just ways to fill the space while waiting for you. The song beautifully expresses a feeling of hopeful patience, dreaming of a time when the person she's waiting for will join her, and they can "play like children" together. It's a sweet and relatable tune about how we occupy ourselves while anticipating a reunion with someone special.