I bought my frenchie from a reputable breeder in Finland about 3 years ago. He cost if I recall correctly 1300€ but he's worth every cent! I love him to bits (: So if the prize range is similar in all Europe, be ready to pay 1000-1500€ if not more.. Plus lifetime costs if the dog happens to have health problems etc, which, unfortunately french bulldogs are quite prone to having..
Frenchies aren't cheap. To get one from a reputable breeder you pay a fair bit, by that I mean thousands. Now they do have rescues and I suggests checking google in your area to see if there are any rescues.