The jewish parts of paris are the Pletzel and Monmarte.
When I was there the main hascha was Beth Din D’Paris. There is a famous deli in the Pletzel called Goldenbergs (or Goldbergs) it is NOT Kosher. even though every other place around it is (Its old time Kosher Deli)
The jews of paris are mostly Sephardim from places you are not used to seeing jews from (Algeria, Tunisia and other parts of North Africa) but they are probably the nicest jews Ive ever met