Median metallicities and V-velocities at different height bins above the Galactic plane. Each point has 1σ uncertainties, obtained from 5 × 10³ Monte-Carlo realisations on the position of the stars (and hence their velocities) and their metallicities. Red diamonds represent the predictions of the raw Besançon model, whereas the blue triangles represent a modified model with metal-richer thick disc and halo, and a thick disc that lags behind the LSR by  km s^-1.