The École des Beaux-Arts was the premier architectural school in France from the 17th century until 1968. In the latter half of the 19th century and early 20th century, over 400 American architects and a few Canadians studied there, some for brief periods in its associated ateliers, others for 9 years or more, receiving the French government diploma.
Students trained at the École, (French, American, Canadian, and Scottish), became the professors heading up the new schools of architecture established in North America and adopting its methods. These included M.I.T., Columbia, Cornell, Pennsylvania and others in the US, and McGill and the École Polytechnique in Montreal. Many more North American architects were educated in the Beaux-Arts method at these schools, including already qualified Canadian architects who took a special 2-year program at MIT.
Canadians who studied at the École include Marchand, Chapman, Vallance, Lyle, Cormier, and (at ateliers only) W.S. Maxwell and Ross . All but Chapman and Vallance designed buildings in Ottawa. Other graduates who worked in Ottawa include Forsyth, Bennett and Gréber. Professors who studied there include Capper, Doumic, Poivert, Despradelle, Lowell, and Cret (see Gréber). Some architects of buildings in Ottawa who studied at MIT include Ross, MacFarlane, Décary and Townsend. Architects working in Ottawa whose former employers or partners studied at the École include Barott, Décary, Ross, and Waid.
The École taught principles of rational design, based on proportion, symmetry, axial planning, progression of spaces, modern structural methods, external expression of interior uses, and an appropriate historical style. A range of actual styles were employed, usually Roman or Greek classical revival, but also Italian or French renaissance revival. Even the post-1925 Art Deco style and the later Modern Classical or Moderne styles could be used with an essentially Beaux-Arts design.
Beaux-Arts architecture was initially also called "Modern French". It is also referred to as "Academic Architecture". In England and to some extent in Canada it has been called "Edwardian Classical, (1901 to about 1914). Often the term "Beaux-Arts" is not applied to a building at all, but only the particular historical style used. In the United States and Canada, even the early Beaux-Arts buildings were largely free of the excessive decoration often found in France and in the buildings of the Edwardian Baroque style.
You can read a variety of quotations on Beaux-Arts architecture.