Correlated flux measured with the ATs, and averaged between 8 µm and 9 µm, as a function of the source flux taken from the MDFC catalogue (Cruzalèbes et al. 2019), without fringe tracker (blue) and with fringe tracker (red). The bias generated by the coherent self-integration disappears when fringes are stabilised and the N-band coherent integration is driven by the phase estimated by the fringe tracker.