A French diminutive of Marie, Marielle is exotic but approachable. My middle name is Marie, which is in honor of my aunt. Probably 80% of the people reading this consider Marie to be a family name, it’s classic! This would be a great way to honor someone named Marie without using the same name. (Though, I do find Marie lovely as well!)
Katia and Marielle Labèque are French sisters known internationally for their piano performances. Check out their performance Rhapsody in Blue on YouTube. They now own their own record label, and represent young artists from several genres. Though they have their own personal lives, they still live together, currently in a palace in Rome.
Marielle Goitschel skied in the Olympics, winning 5 medals, 3 of them gold. Another famous sister set, Marielle and her older sister Christine were the first sisters to compete in an individual Olympic event against each other. Their first event Christine won gold and Marielle silver, the 2nd they flopped the order of their victories. I guess with this association as well as the one above, Marielle is the perfect little sister name.
2 members of the French parliament are named Marielle, which I think makes the name more powerful and passionate. Marielle Houle is a well known Canadian criminal who helped her sick son commit suicide. Obviously, to some this would be a terrible association, but to some, this namesake represents a very loving mother. To learn more about these and other Marielles, check out Wikipedia.