We study the long-range one-dimensional Riesz gas on the circle, a continuous
system of particles interacting through a Riesz (i.e inverse power) kernel. We
establish near-optimal rigidity estimates on gaps valid at any scale.
Leveraging on these local laws and using a Stein method, we provide a
quantitative Central Limit Theorem for linear statistics. The proof is based on
a mean-field transport and on a fine analysis of the fluctuations of local
error terms through the study of Helffer-Sj\"ostrand equations. The method can
handle very singular test-functions, including characteristic functions of
intervals, using a comparison principle for the Helffer-Sj\"ostrand equation