Comparison of the age of the main stellar population measurements of galaxies in the reference catalogue and AGN for the estimated and true values from the mock analysis. For both populations, CIGALE overestimates the parameter at < 3000 Myr. The trend is more evident in the case of X-ray sources. The algorithm underestimates the parameter for older stellar ages. Errors represent the standard deviation of the measurements. AGN measurements have been offset by 50 Myr on the horizontal axis for clarity.