If you go thinking you won't like it you may well see the negatives and not enjoy it. If you go go with an open mind. Don't just go to tick a box.
I've been visiting Paris for 40 years. I have lived here for full time for 6 years ( I say here as I am now sitting in my Paris apartment). I now visit a few days every month from our home in rural France to visit DS who is at Grande Ecole here. DS was born in Paris 21 years ago. So I have known it quite well for a long time.
It is like every other big city (I have lived in London, Rome and Edinburgh as well). Good and bad bits. I find the amount of tourists a bit oppressive now at times but I did think that has made customer service in restaurants and shops much better. The younger staff aren't as surly as a few years ago. For meals in restaurants the price compared to the quality has really improved in the last 10 years.
Hidalgo has been rather a controversial mayor but she has made the city cleaner and much more pedestrian friendly..
As a first time visitor there are so many things to see and do. You just have to plan it, depending on what your interests are. If you do come just take one day to have a walk and enjoy a long lunch.
Where to stay? It's very subjective but we always lived in the 15th near Motte Piquet/Cambronne. Now it's a bit too full of tourists for me. A couple of stops up line 6 metro the area around Montparnasse station is not as seedy as some of the areas around big train stations, is still reasonably tourist free and has some great cafes and restaurants and good transport links. If I had to stay in a hotel it would be around there near to Edgar Quinet metro. I would absolutely not stay in arrondissements 1-9, apart from some places in the 6th. . Too noisy, crowded and hit and miss with restaurants (despite what I said earlier about quality improving). Passy in the 16th is also nice. Not many tourists and a real village feel with the shops and restaurants.
Best time to come I would probably say April or September. The weather is generally good but not too hot. Nice enough to sit outside but not oppressively hot. August as someone mentioned can be good but it can be very hot. Also some traditional shops still close for the whole of August. My bit of Paris all the small shops close then.
You do get scammers but not as much as a few years ago. The difference here is you tell them to get lost and they go immediately. Unlike Rome. People here are generally nice honest people. DS lost his wallet a year ago and someone picked it up and handed it in to the police on the same day. I have no problems walking around late at night on my own. I feel safer here than any other city I have lived in.
Paris like most places is what you make of it. I love it warts and all. Of all the places I have lived this is my favourite.
But as I said if you are doing it to tick a box don't bother. You probably won't enjoy it.