From January to June of this year, a million fewer people visited Paris compared with the same period in 2015.
If you follow the news, you shouldn't have trouble figuring out the reasons for this sharp dropoff: recent attacks by Islamist militants in Paris as well as other locations in France including Nice and Normandy. Labor strikes and flooding in the French capital earlier this year have also hurt tourism.
Since Paris customarily gets 16 million visitors a year, 2016's decline is estimated to have cost the city 750 million euros in lost revenue so far.
Our own Arthur Frommer argues that the slowdown actually might make this a good time to visit Paris if you're looking for hotel bargains and uncrowded attractions. Tightened security measures—including a visible military presence—have likely made your chances of falling prey to terrorism lower than they already were.