Okay, I may be overstating a bit, but the French capital isn't exactly awash with fixies. Or maybe the people who ride them just aren't too keen on leaving their priced possessions outside. Who knows?
Judging from what you see in the streets, the French bicycle industry went out of business in the '70s: Most of the bikes you pass look ancient, and few of them are well-kept. Paris is quite hilly, so people are really into geared road or racing bicycles, and many ride with their drop bars flipped, but not chopped, resulting in a setup that looks absolutely deadly in case of a crash or collision.
It seems that the French bicycle factories like Motobecane, Gitane and Peugeot all had a nasty habit of using weak alloys for their head stems; I even managed to break one while attempting to salvage it from an old wreck. So much for durability.
My friend Tom, who works as a bike messenger in Paris, explained that there is a strong tradition for using scooters instead of bicycles, and with the characteristic French sense of intrigue, he also added that there is a bit of animosity between the oldschool fixed gear riders and all the newcomers who jump on the trendy wagon. They just love a bit of bickering down there, don't they?
I'll post some more images when I have them developed & scanned.