Vets in the region between East Loire and Dunkirk

We are taking our medium sized dog to France for the first time in June 2012, spending time mainly in the Loire valley moving west to east, then home from Dunkirk.  We need to visit a vet for tapeworm treatment between 1 - 5 days before our return.  Can anyone recommend a vet in the region between eastern Loire valley and Dunkirk?  Would be most grateful for help.