I'm breeding for a shiny with 5IV. The male is a 6IV french pokemon and the female is a 5IV from my game (ENG). I've got a female 6IV and i was wondering if using her would ruin my chance of shiny since the female would be the offspring of the foreigner. (I heard somewhere that it was the case, but only once.)
To be honest, I'm not sure. If you decide to use the 6iv female instead of the 5iv then I would assume it would break your chain since its not breeding with the 5iv one. If you want the shiny to get better chance for good ivs then breed with the 6iv female. that is what i did when i was breeding for a shiny onix.
It shouldn't. You said that the MALE was french. So if you sub out your FEMALE 5IV with the 6IV shouldn't ruin your chances because you still have the French Male.