Age-Metallicity relation for the sample of clusters with ages between 1 and 3 Gy, divided in three radial bins. The clusters observed by Gaia are represented with semi-transparent circles, while those observed by GES with solid-filled circles. The linear regressions are shown with dashed lines using the same colour as the corresponding radial bin. In the plot, we show the coefficients of the three age-metallicity relationships. The size of the symbols is proportional of the number of member stars used to compute the mean values.