The best commercially marketed source for concentrated stocks in the US, Aromont, no longer carries their old French-made products.
Elsewhere I have been trying to find something comparable. A few months ago in Paris I purchased two Belgian-manufactured Nestle concentrés that while better than anything I have found in the States are still inferior to the best Aromont used to carry.
Is there any shop in Montreal that might have a special selection? What brands are available? I know the gourmet shop in Atwater Market. I doubt the Le marché des saveurs in the Jean Talon market would have anything like what I am seeking. It may very well be a food shop that specializes in French imports.
In Montreal supermarkets I regularly buy the Knorr Bovril bouillon concentrates (beef and chicken), half liter size, which I have not seen in the States and are far superior to dry bouillon cubes, but they are inferior to a true demi-glace that is made from a reduction of roast meat, bones, vegetables, and spices and in the case of Nestle concentrés, a baffling array of chemicals.