Minimal paint damage opposing exterior mirror, but pre-damage ! How to behave ??

Hello, I have striped a car on the (painted) exterior mirror, only minimally scratched. However, when I examined the opposing damage, I saw that the exterior mirror already has other paint damage, such as scratches and overpainted “paint bubbles” or something like that (a kind of outline that signified under the top coat of paint) Without an accident report being filled out, only telephone exchange, I separated myself from the accident opponent. It doesn’t. Photos yes, but mine have not become anything, because I have a bad mobile phone and you can hardly see the damage anyway. You can’t delimit the damage reasonably from the other paint defects !! As expected the lady called me afterwards and said she had now obtained an offer : 80 € should cost the repair, 40 € of which I should wear. I don’t see. First, the lady has parked so that you could hardly get through at the appropriate place, second, was She was constantly overreacting (he was annoyed) and after that I received a threatening SMS from her husband in the evening that one will turn on the police. (this is not possible to my knowledge, because it is not an accident escape, therefore purely private law thing….) P.S.: the accident happened in France at a nearby gas station. Does it make a difference ?? How should I behave ? I thought I could propose to pay 20 €…..or NIX