Tell her to watch her handbag. My wife got her purse stolen whilst we were travelling on the crowded Metro underground. Personally, I think Paris is way over-rated. Not in the same league as London, Venice or Rome. Yes there are about 10 tourist spots worth visiting but in between it hasn't got the character of other major European cities.
I'd argue the opposite; it's got the worst tourist spots but the rest of the city puts it only behind London in the world for me. Saying that, I could imagine how a negative experience like your wife getting her handbag stolen could colour how you viewed the city. It's got character by the bags if you know where to stay, where to eat, and where to go out to; you just have to go a few times to find your way around the place. It's definitely worth the effort though. Huge plus if you speak the language, makes everything far easier and your experience will be way more enjoyable as a result. Even if you garble a handful of French words, the locals will appreciate the attempt and then talk to you in English!
That’s brought back two random memories: 1) when I went on an organised coach trip to Paris and one evening they took us to the ‘Latin Quarter’ with some fabulous little bars on a tiny side street and I’ve never been able to find it again. and 2) trying to think of the French for ‘bubble bath’ and trying to mime it in a supermarket. We had to give up in the end after some very weird looks.