I have learned not to trust this site too much when it comes to the usage of a name. A lot of English names are used in the Netherlands as well and that's never stated here. I've never actually met a French girl named Fleur but I'm sure they use it, it's very nice!
Between 1900-2006, 3421 babies were named Fleur in France. 158 in 2006. A very uncommon but old French name. St Fleur of Beaulieu (also known as Flora) is notable as is the Harry Potter character.