As a previous foreign entrepreneur who lived in Paris for 8 years here's my experience and my advice: In paris entrepreneurship is a VIP club for rich people who will rarely take real risk. Seed investment is next to impossible. The tax reduction schemes requires months of procedures and administrative paperwork. Real estate is almost as expensive as London. And the worst, if you're a foreigner you'll have a real hard time given all the immigration laws nonsense.
You're better off making your startup almost anywhere else.
EDIT: and as other comments said, people don't speak English, the French have some sort of pride of only speaking their native language ...