Filet of Filley???
Thanks to Brigitte Bardot and the very successful "lutte contre l'hippophagie", horse meat is pretty much of a no-no... just a handful of boucheries-chevalines remain in Paris and these seem to cater mostly to elderly scarved women who throw on a raincoat over their nightdresses to do their "courses"/ shopping errands ... there used to be one on the rue Poteau near your apartment but I'm not sure if it still exists... if it does, ask the guy what local restaurants he supplies (if any).
Maybe some restaurants like Louchebem in Les Halles might have it OFF the menu but you'd have to ask the waiter (in a whisper) if it's available... the only restaurant that persists in advertised "hippophagie" is a cabaret sort of place near Ternes (17e) that specializes in donkey steaks and xenophobic comedians.
To redeem yourself in the eyes of pikawicca, I suggest you make a little trip in March to Auteuil in the 16th, Saint-Cloud or Fontainebleau hippodromes for the races or to Chantilly for the horse museum and riding exhibitions in the chateau's stables. This is the best way by far to enjoy horse flesh.
If looking for a chevaline, a horse butcher, two still functioning ones are on Rue Cadet on its market st and at the Sunday market at Bastille about half way up on the right just after a gap in the market. While this guy is grumpy, at least to me, he does have filet. If you are doing this to try it it, do filet, light cooking and quite interesting, meat is sweeter than most other meats, and as cooked less than other cuts will have a truer taste.
I'm a little surprised to see these guys reporting that cheval is hard to find in Paris.
Out here in the provinces, there's a chevaline (horse butcher) with a stall in a prime corner spot in our covered market, two more chevalines with storefronts, and absolutely no shortage of cheval in ANY supermarket (Intermarche, Auchan, Carrefour -- hyper and Market, Leclerc, Casino).
I don't eat it (yes, I've tried it, and don't care for it) -- but it's harder to avoid than to find.
Interesting that it would be so different than in the city.
Now -- on a menu? I don't remember the last time I saw cheval on a restaurant menu.
Paris is, fortunately, very different from les provinces ... horse meat is not hard to find but just not as easy as it used to be... my grandmother tells me that 50 years ago you could find horse meat here in every street market and on every market street but now there are probably no more than 15 boucheries-chevalines left in Paris ... i've occasionally seen viande de cheval at the Marché Aligre and the Marché Bastille but not in my more usual street markets or local supermarket (in the 6th).
Viande de cheval was always considered a meat for the working classes because it was so cheap ... but it ain't cheap anymore ... and the old working class has gradually shrunk and morphed... there is also a feeling/ urban myth among the under-40s that horsemeat-eaters are supporters of lunatic far-right groups.
and yes, very very rare on restaurant menus ... you're more likely to find it in a Tuscan or Sardinian restaurant in Paris than a French one
"Paris is, fortunately, very different from les provinces ... "
Fortunately, indeed… ;)
Here's a list of horsemeat butchers in Paris:
And this (French) restaurant in the center of town appears to have horse on the menu: