Help

[Taz28061975]

I’ve just bought a 207 I get antipollution fault on dash I’ve put cat cleaner in doesn’t seem to have worked it comes on every 2nd start of engine I have looked on my OBD machine and it’s saying these faults is it the
Rear O2 sensor or front O2 sensor ? Any help would be greatly appreciated I have also cleaned the Variable Valve Timing Solenoid