Columbia subject headings:
Exhibitions--France--History--20th century--Congresses.
Technological innovations--Social aspects--France--History--20th century--Congresses.
Trade shows--France--History--20th century--Congresses.
Harvard subject headings:
Trade shows--France--History--19th century--Congresses.
Princeton subject headings:
Trade shows--France--History--19th century--Congresses.