Dormir à la belle étoile, literally “to sleep under the stars”, means to sleep outside! Maybe you’ve done that while backpacking? Before, It was used ironically, as if “La Belle étoile” (the beautiful star) was the name of an inn. And well, if you were sleeping at “La Belle étoile”, then the ceiling was full of star!
Dormir à la belle étoile
French with Valerie 