We don’t know the full back story but from my experience French girls like to stir up a bit of emotion in the men they are interested in. She has no idea about cars but she has noticed yours’ is a bit different and is obviously important to you. By insulting it she’s playing you. I suspect you could end up in bed with her and it could be quite exhilarating (but as per previous be prepared for hairy armpits, garlic/coffee breath and filthy behaviour).
BTW are the French not renowned for favouring cheap cars?