I would like to present a recent work in collaboration with T. Banerjee, S. Majumdar and G. Schehr on the distribution of the flux through the origin up to time t, in noninteracting one-dimensional (active) run-tumble particles with a step initial condition. While at large times the typical fluctuations of the flux are indistinguishable with respect to standard brownian particles, the fingerprints of the activity remain present and are at the origin of an anomalous large-deviation form.