We found a couple of places to buy caviar in Paris and I thought I would pass them along. Caviar Latian is a small storefront near us in Passy on Rue de l'Annonciation. Apparently they have been around since 1994 and offer both farmed and wild products. They have Baeri caviar all of the time, and intermittent supplies of Beluga, Schrenki and Ossetra. They also sell salmon, a variety of other fish, vodka and caviar accessories like blinis and mother of pearl spoons.
They have a live Acipenser Baeri sturgeon in a tank, sort of a gruesome mouth on these fish. You can see from the menu that they get the caviar from all over. They didn't have any Buluga, they said they only get it at Christmas, we got the Schrenki Imperial which is also known as the Amur or Japanese Sturgeon. It is found in the Amur river basin in Russia and China where it is also farmed. They also have made a hybrid wild species: Huso Dauricus & Acipenser Schrenckii especially for farming. The Kaluga (Huso dauricus) is a large predatory sturgeon found in the Amur River basin. Also known as the river beluga, they are claimed to be the largest freshwater fish in the world, with a maximum size of at least 1,000 kg (2,205 lb) and 5.6 m (18.6 ft).
We bought a small tin, along with some blinis and a mother of pearl spoon for 3€ and took it home. They actually package it in the back to order. We warmed up the blinis and had it with goat cheese, one of my favorites although a warm Brie is also good. This was the best caviar we have had in France, and at a good price, I would recommend the caviar if you are in the market for some.
Another place to find caviar is at the Galleries Lafayette at their gourmet store but you will pay a steep price for it. They obviously get their caviar from Petrossian. As I have said before, you cannot buy Buluga in the US, so this is a real treat. Surprisingly the Petrosian restaurant seems to have gone downhill, judging by the reviews on TripAdvisor. If you want really good caviar in a fine restaurant, consider Caviar Kaspia in the 8th instead.
Caviar Latian: http://caviarlatian.com/
Caviar Kaspia: http://www.caviarkaspia.mobi/