Notes. Column (1) states the galaxy name, while Cols. (2) and (3) provide the inclination and position angle of the galaxy disc (Muñoz-Mateos et al. 2015). Columns (4)−(6) state the total stellar mass of the galaxy derived within S⁴G, the spatial scale of the observations, and the kinematic radius of the nuclear discs (see G20), respectively. Column (7) states whether the morphology of the Hα emission is dominated by a nuclear ring (NR), central emission (C), a uniform nuclear disc (U), an irregular emission pattern (IRR), or no ionised gas emission throughout the field of view (NO). In Col. (8) we provide the ionisation source in the innermost region of the galaxy (at r ≪ R_kin), as determined with BPT-diagrams (we note, nonetheless, that the main ionisation source in the nuclear rings the majority of the radial extent of the nuclear disc is star formation). Column (9) describes the shape of the age profile inside/outside of the nuclear disc as symmetric (“SYM”) or flatter within the nuclear disc (“FLAT”). This classification is given only for the non-star-forming galaxies, as the age profiles are often hard to distinguish in the other subsamples. In NGC 1291 and NGC 4371 the age profiles are dominated by the inner bar and projection effects, respectively, and, thus, we omit these galaxies in this classification.