Likely a modern blend of Gene and -elle, influenced by French feminine styling.
Gennelle is likely a modern blend of Gene and the feminine French-style ending -elle. That combination gives it a smooth, decorative shape that feels both familiar and newly made, like a name assembled from sounds that already carry elegance.
It does not belong to an old established line so much as to the modern habit of making names by layering recognizable fragments into a distinctive whole. The result is a name that feels soft, polished, and gently diminutive without becoming childish. Gennelle has the kind of balanced finish that makes it easy to imagine in both formal and intimate settings.
It sounds contemporary, but with enough French styling to keep it from feeling purely invented. Gennelle has a light, graceful energy, the sort of sound that suggests refinement with a personal touch.