Is there any special reason why French people love that place?
I was kidding Sedna.
Kazimierz is my favorite part, plenty of good bars and dinning places.
There are many clubs, resturants etc. and new commers always asks people's opinion, I think instead you should discover yourself and make your own impression of the individual places.
Either way don't worry, Krakow is an amazing and you'll love it for sure. I know many french guys in Krakow, they never plan on moving back.