Taking our dog to France next year

We will be travelling to France again next year. This time however we will be taking a little Cocker Spaniel " Holly" with us. She has been chipped and has her passport. What I am a little in the dark with is what I need to do regarding the "Tapeworm" check prior to coming home. Our last stop is St Valery Sur Somme and would like to find a vet within that city prior to boarding the Euro Tunnel home. Does anyone know of a vet in St Valery Sur Somme that will not try to "rip me off"? One with an email? Shoul I book the vets service ahead of time? What should it cost roughly? Can I get some kind of extra insurance to cover this work? Can the treatment upset the dod in some way? Your help please. Many thanks.