Unless you enjoy getting harrassed by aggressive beggars, random people trying to "show you a fun trick" that you'll then be expected to pay 20€ for, or at best, people trying to get you to buy something you don't need, I recommend avoiding pretty much all the main tourist hotspots in Paris. The worst-affected areas in my experience are Montmartre, the square in front of the Notre-Dame, and to somewhat lesser extent, the Tuileries gardens. I haven't gone anywhere near the Eiffel tower for the precise reason in the last few times I've been there - my first trip to Paris was 10 years ago and things have really deteriorated since then. If you're desperate to see the main sights, then avoid going alone and keep moving. I was immediately targeted by someone or several someones each and every time I had to stop to wait for my boyfriend who was taking pictures.
The good news is, there is plenty to see all over Paris, plus the food is noticeably cheaper in the less touristy areas, and, provided you're being polite and saying your "bonjours", "mercis" and "au revoirs", the people there are friendlier towards foreigners.
Is this your business?