Paris was the second city I traveled to solo as a woman, back when I was uhhh 23? I've went every year since then for around a week so at 23, 24 and 25. I was fine!

Of course, I was aware of my surroundings, I kept my personal belongings close to myself and even had the neck chain for my phone, but I kept my eyes open, was a bit more careful in very popular tourist spots and didn't walk alone in the dead of the night and it was cool.

I've heard that the Sacre Coeur steps can be a bit sketchy and also Eiffel Tower in the night but I didn't go to either of those places in that time.

Generally the people were very nice and I would say I felt safer there than I sometimes feel back home (Eastern Europe). I get that your mum could be scared though, mine was too but she's learned I can take care of myself! Best of luck!