I have seen an opposite trend. I see more and more people coming to get married in France
Maybe the big change is on the origin of the people coming, but there is no decrease in th eamount of foreigners coming to get married here. There seems to be a considerate number of Asian couples coming to tie the knot here in the most lavish weddings you can imagine. We have lots of castles for rent for this purpose and they never run out of business.
...but if you still think that France is worth trying, you can be rewarded with amazing venues like this one http://www.wherewedding.co.uk/others-chateau-st-julien.html and then all struggles become unnoticable :p