Actually, frog eating is a cliché. We never eat frogs. In 35 yrs I ate some only once, when a kid (that was pretty tasty). Older generations probably ate some but now it is a (almost) lost culinary habit. On the other hand, we eat Burgundy snails cooked with garlic. Very tasty (but foul breath after :-), you can probably try it during your stay (with some Burgundy wine...) ;-)
Oh forgot your initial question : "Does anyone how to eat a frog in France ?"
Well, with a knife and fork.
But you can try frog-burger with your fingers if you want, my american friend, just think about removing the tiny bones before... lol
The funny thing is that I, being from South Carolina, have probably eaten more frogs than anybody in Burgundy.
I think the english started the whole thing about frogs. Which is bloody ironic considering black pudding...