A pretty, Frenchified nickname of Cecilia that would work well on its own, perhaps as a reference to an aunt Cece.

Sisley may look like a modern coinage, building on the fashionable -ley ending, but it's actually a medieval English variant of Cicely or Cecily, which in turn is a variation of Cecilia. Also found as an English surname, from the same root.

Variant of Cecilia used in several European countries, which could also make for a pretty variant spelling of the medieval English version, Cecily.

Danish diminutive of Cecilia