I lived in France before actually there are two China Towns in Paris.
I suggest you to buy go the one in the 13th District (take metro Ligne 7 and get off at Porte D'Ivry station)
The street is Avenue D'Ivry. There's a small shopping mall near Paris Store (a Chinese supermarket) and there some Chinese or Southeast Asian shops and restaurats. You can find a shop selling sim card and cell phone accessories)
Another China Town is located in the 19th/20th District, it's called Belleville where many restaurants or shops are owned by
Mainland Chinese. I heard it's quite dangerous there.