What are the downsides to living in Paris?

Hey

I did a semester abroad while I was at university around 10 years ago now. I was utterly in love with expat life in the city and I've always dreamt of going back. My husband recently got an exciting job offer in the city, which would allow both of along with our 3 year old son to relocate to Paris for 2 years. I'm super excited about going back, but my husband is apprehensive about the language barrier for us, but mainly our son and also how we'd intergrate as Americans into local Parisian society. His colleagues tell him city residents are really unfriendly, that is not what I remember though. I suppose things could have changed.

Are there any expats living in Paris who could tell us a little bit about the reality of expat life in Paris? What are the downsides of living in the city? Are people really unfriendly? 

Look forward to getting your insights.

Cheers

Anya