My guess is that your mother is terrified of being on her own. Instead of dealing directly with her anxiety, she is trying to avoid the whole thing by keeping you with her. You are 25. You have two obstacles that are getting in the way of thinking this through clearly. You have a big heart and you have been worn down by your mother’s anger. You don’t want to abandon your mother but you do want, at 25, to start living your own adult life.
I wish I knew what social services are available in your city. I don’t, so I can’t give you direct guidance. Since your mother isn’t interested in helping herself, I’m afraid you will need to do the research to find out what services are available for impoverished seniors. A good place to start might be the senior services in Paris. You mother may be eligible for housing, for example. If you can find some practical alternatives to being dependent on you, your mother may be less afraid — and therefore less abusive.
I also urge you to consider getting some therapy for yourself — not because I think you have a mental illness but because I think you need the support and practical help a therapist can offer. Extricating yourself from this situation in a way that feels okay is going to take effort. You deserve that support.
I wish you well.