The study of articulatory complexity has proven to yield useful insights into the phonological mechanisms of spoken languages. In sign languages, this type of knowledge is scarcely documented. The current study compares an error-driven measure and a model-driven measure of complexity for signs in French Sign Language (LSF). The former measure is based on error rates of handshape, location, orientation, movement, and sign fluidity in a repetition task administered to non-signers; the latter measure is derived by applying a feature-geometry model of sign description to the same set of signs. A significant correlation is found between the two measures for the overall complexity. When looking at the effects of individual phonological classes on complexity, a significant correlation is found for handshape and location but not for movement. We discuss how these results indicate that a fine-grained theoretical model of sign phonology/phonetics reflects the degree of complexity as resulting from the perceptual and articulatory properties of signs.