According to aerodynamics, fighter jet's turn rate rely more on a lower wing load, however, the MirageF-1's wing load were pretty similar with the F-8 crusader which maximum turn rate was 14d/s, whereas some source online alleged a 20 d/s of ITR for Mirage F-1. It will be unthinkable where was the data taken.....
I watched the video Sungsam posted here, in which played an impressive roll rate by Mirage F.1, however the camera set in cockpit didn't suggest such high roll rate could be performed by pilot.
The G limit graph dawn by Falcon4 showing 20 d/s ITR either without releasing reason.