The Franco-Prussian War lasted less than a year, but it was a particularly hard time for Paris. The Germans surrounded the city and began a siege. No one could get out, nor could supplies be brought in, for five months. As winter approached, food was running out. Restaurants stayed open, although they had no agricultural products. One waiter snapped at a woman who wanted a salad, “Madame, this is a restaurant, not a meadow!” So what was on the menu? Meat. First they ate the horses, then the cats and dogs, and then rats. And the animals of the city zoo.
The restaurant Christmas menus from 1870 reflect what was available, and how eateries did their best to make it sound palatable. At the restaurant Voisin, you might have elephant soup, fried camel nuggets, kangaroo stew, or bear chops, among other ghastly offerings. But the most common food was from cats, dogs, and rats. Butchers began to specialize in slaughtering household pets. We don't know how long Parisians would have held out eating such food, because Otto von Bismarck lost patience and shelled the city into submission. Read about the dreadful Parisian diet of 1870-1871 at Messy Nessy Chic.
Maybe it's better if you just don't know whose d'oeuvres they are...